UC-NRLF 


GIFT  OF 


BIOV-C 
RA 
G 


FIRST   BOOK 


OP 


ZOOLOGY 


BY 


EDWARD    S.    MORSE,   PH.D., 

LATE  PEOFESSOE  OP  COMPARATIVE  ANATOMY  AND*  ZOOLOGY  IN  BOWDOIN  COLLEGE. 


"  As  for  your  pretty  little  seed-cups,  or  vases,  they  are  a  sweet  confirmation  of  the  pleasure 
Nature  seems  to  take  in  superadding  an  elegance  of  form  to  most  of  her  works,  wherever  you 
find  them.  How  poor  and  bungling  are  all  the  imitations  of  art !  When  I  have  the  pleasure 
of  seeing  you  next  we  will  sit  down— nay,  kneel  down  if  you  will— and  admire  these  things." 
— [HOGARTH  in  a  Letter  to  ELLIS. 


NEW  YORK: 
D.   APPLETON  AND   COMPANY, 

549    AND   551    BROADWAY. 
1879. 


ENTERED,  according  to  Act  of  Congress,  in  the  year  1875,  by 

D.  APPLETON  &  COMPANY, 
In  the  Office  of  the  Librarian  of  Congress,  at  Washington. 


PREF  AC  E. 


THE  "  First  Book  of  Zoology "  is  expressly  prepared 
for  the  use  of  pupils  who  wish  to  gain  a  general  knowl- 
edge of  the  structure,  habits,  modes  of  growth,  and  other 
leading  features  concerning  the  common  animals  of  the 
country. 

Particular  attention  has  been  given  to  the  lower  animals, 
as  these  are  more  often  neglected  in  text-books.  Directions 
for  collecting,  the  preparation  of  specimens  for  the  cabinet, 
and  the  haunts  of  the  animals  to  be  studied  are  given,  and 
the  pupil  is  expected  to  study,  with  the  book  in  one  hand, 
and  the  specimens  in  the  other.  The  figures  illustrating  this 
work,  with  a  few  exceptions,  have  been  drawn  from  Nature 
by  the  author,  and  have  been  prepared  with  especial  refer- 
ence to  their  being  copied  by  the  pupil.  To  facilitate  this 
the  figures  are  made  in  outline,  with  the  shaded  side  of  the 
figure  indicated  by  darker  lines. 

256329 


iv  PREFACE. 

The  necessity  of  the  pupils  copying  (however  poorly)  the 
figures,  either  upon  the  slate,  or  upon  paper,  cannot  be  too 
strongly  urged. 

From  his  own  experience,  the  author  has  learned  that  a 
specimen  or  figure  may  oftentimes  be  carefully  studied,  and 
yet  only  an  imperfect  idea  be  formed  of  it ;  but,  when  it 
had  been  once  copied,  the  new  points  gained  repaid  all  the 
trouble  spent  in  the  task. 

It  makes  but  little  difference  whether  the  pupil  is  profi- 
cient in  drawing  or  not ;  it  should  be  strenuously  insisted 
upon  by  the  teacher  that  the  pupils  copy,  as  far  as  possible, 
the  figures  contained  in  each  lesson. 

To  collect  in  the  field,  to  make  a  cabinet,  and  then  to  ex- 
amine and  study  the  specimens  collected,  are  the  three  stages 
that  naturalists,  with  few  exceptions,  have  passed  through  in 
their  boyhood. 

If  one  recalls  the  way  in  which  boys  first  manifest  their 
taste  for  such  studies,  he  will  remember  that  first  a  few  ex- 
amples were  brought  together ;  a  collection  was  made.  It 
may  have  been  birds' -eggs,  insects,  or  shells;  then  little 
boxes,  a  case  of  drawers,  or  shelves,  were  secured  to  hold 
their  treasures.  In  thus  collecting  and  arranging  and  rear- 
ranging the  cabinet,  the  eye  becomes  familiar  with  the  out- 
line and  general  character  of  the  objects,  and  in  this  way  the 
mind  is  finally  prepared  to  comprehend  the  relations  existing 


PKEFACE.  v 

between  animals,  and  to  appreciate  the  leading  points  upon 
which  classification  is  founded. 

Agassiz  invariably  placed  before  his  students  a  single 
specimen,  or  a  box  full  of  specimens,  and  told  them  to  look 
and  see  what  they  could  find  out. 

It  has  seemed,  therefore,  that  the  way  to  commence  the 
study  of  zoology  is  to  follow  the  course  one  naturally  pursues 
when  he  is  led  to  the  study  by  predisposition.  Nor  is  it  es- 
sential, at  the  outset,  to  present  the  entire  range  of  the  ani- 
mal kingdom.  Teach  the  characters  of  one  or  two  great  di- 
visions first,  and  then  the  pupil  is  better  prepared  to  grasp  in 
turn  the  other  divisions.  The  persistent  attempt,  in  all  text- 
books of  this  kind,  to  give  some  attention  to  every  large 
group  in  the  animal  kingdom,  has  often  resulted  in  wearying 
and  confusing  the  minds  of  those  who  take  up  the  study  for 
the  first  time. 

A  very  serious  difficulty  is  encountered  in  those  books 
which  give  a  more  or  less  complete  view  of  systematic  zo- 
ology for  beginners.  In  some,  the  authors  commence  with 
the  lowest  forms,  and  end  with  the  highest.  In  others,  the 
highest  animals  are  dealt  with  first,  and  the  lessons  end  with 
the  lowest.  The  first  mistake  made  is  the  attempt  to 
teach  systematic  zoology,  where  the  pupil  is  quite  ignorant 
of  the  material  to  be  classified ;  and  proper  familiarity 
with  the  objects,  the  author  contends,  can  only  be  acquired 


VI 


PREFACE. 


by  collecting  the  specimens  and  forming  a  little  cabinet  of 
them. 

The  difficulty,  however,  arises  in  commencing  the  les- 
sons with  either  the  lowest  or  the  highest  animals.  If  the  au- 
thor commences  with  the  lowest  animals,  he  deals  at  the  out- 
set with  creatures  which  the  pupil  in  certain  cases  can  never 
see,  as  many  of  the  animals  to  be  considered  are  microscopic, 
and  most  of  them  of  such  a  nature  that  their  soft  parts 
cannot  be  preserved.  On  the  other  hand,  if  the  author  com- 
mence with  the  vertebrates,  he  presents,  point-blank,  some 
of  the  forms  of  structure  most  difficult  to  understand. 

The  main  thing  at  the  outset  is  to  teach  the  pupil  how 
to  collect  the  objects  for  study ;  this  leads  him  to  observe 
them  in  Nature,  and  here  the  best  part  of  the  lesson  is 
learned :  methods  of  protection  for  the  young,  curious 
habits,  modes  of  fabricating  nests,  and  many  little  features 
are  here  observed,  which  can  never  be  studied  from  an  or- 
dinary collection.  Hence,  collecting  in  the  field  is  of  para- 
mount importance.  Next,  the  forming  of  a  little  collection 
at  home  prompts  the  pupil  to  seek  out  certain  resemblances 
among  his  objects,  in  order  to  bring  those  of  a  kind  together. 
In  this  way  he  is  prepared  to  understand  and  appreciate 
methods  of  classification.  Finally,  having  grasped  the  lead- 
ing features  of  a  few  groups,  he  is  enabled  to  comprehend 
the  character  of  cognate  groups  with  less  difficulty.  Thus, 


PREFACE.  vii 

an  inland  student,  having  got  the  typical  idea  of  an  insect 
from  the  study  of  a  common  grasshopper,  for  example,  is 
much  better  prepared  to  understand  the  general  structure 
of  the  Crustacea,  though  he  may  never  have  seen  the  few 
forms  peculiar  to  fresh  water.  In  the  same  way  after 
having  studied  the  common  earthworm,  he  can  form  a 
better  idea  of  the  complicated  structure  of  many  marine 
worms,  though  these  he  may  never  see.  After  long  delib- 
eration, and  some  hesitancy,  the  author  is  forced  to  depart 
from  common  usage,  and  present,  in  this  first  book,  only  a 
few  of  the  leading  groups  in  the  animal  kingdom. 

From  the  abundance  of  material,  and  the  comparative 
ease  with  which  the  specimens  may  be  preserved  for  cabinet 
use,  shells  and  insects  have  always  formed  the  favorite  col- 
lections of  children.  They  are  the  most  common  objects  in 
nearly  all  collections,  and  it  has  seemed  to  the  author  that 
here  the  pupil  ought  to  commence  his  studies. 

Having  learned  to  collect  and  prepare  specimens  for  the 
cabinet,  and  to  observe  the  relations  and  differences  existing 
among  them,  the  pupil  is  then  prepared  to  go  on  to  forms 
less  familiar,  or  to  study  in  detail  the  material  already  gone 
over. 

Great  pains  have  been  taken  to  present,  in  every  case, 
drawings  made  from  the  animal,  expressly  for  this  book. 
They  are  all  American,  and,  with  few  exceptions,  are  en- 


viii  PREFACE. 

tirely  new.  It  is  believed  that  teachers  will  appreciate  the 
absence  of  those  hackneyed  illustrations  which  have  too  long 
done  service  in  text-books  on  the  subject. 

To  those  especially  interested  in  the  study,  many  figures 
are  given  which  have  never  before  been  published,  even  in 
scientific  works,  as,  for  example,  the  rare  Lymncca  mega- 
soma,  Lymncea  ampla,  Ptyelus  lineatus,  and  many  others. 

I  desire  here  to  express  my  thanks  to  Dr.  A.  S.  Packard, 
for  looking  over  the  pages  relating  to  insects,  and  to  Dr.  H. 
Hagen,  Mr.  Samuel  H.  Scudder,  Prof.  H.  H.  Straight,  Prof. 
Theodore  Gill,  Prof.  A.  J.  Cook,  and  Miss  Maggie  W. 
Brooks,  for  important  specimens  for  illustration ;  and  to  the 
firm  of  Russell  &  Eichardson,  Boston,  who,  with  the  interest 
of  personal  friends,  have  attended  to  the  proper  engraving 
of  my  drawings.  I  am  also  deeply  indebted  to  Prof.  E.  L. 
Youmans,  Mr.  John  M.  Gould,  and  Mr.  Henry  W.  Swasey, 
for  valuable  suggestions  and  advice ;  and,  finally,  I  have  to 
express  my  gratitude  to  the  publishers  of  this  book,  who 
have,  with  unbounded  liberality,  left  the  entire  matter  of 
illustration  in  my  hands. 

E.  S.  M. 

SALEM,  MASS.,  March  12,  1875. 


NOTE  TO  SECOND  EDITION. 


WITH  the  printing  of  the  second  edition,  the  author  desires  to  thank 
the  press  throughout  the  country  for  the  generous  praise  they  have 
awarded  this  little  book. 

He  wishes  also  to  express  his  gratitude  to  the  numerous  friends  and 
teachers  who  have  kindly  pointed  out  some  errors,  which,  it  was  ex- 
pected, would  escape  observation  during  the  hurried  passage  of  the  book 
through  the  press  that  it  might  be  ready  for  the  opening  of  schools. 

To  Mr.  O.  S.  Westcott,  of  the  Chicago  High  School,  the  author  is 
especially  indebted  for  many  valuable  suggestions,  made  after  a  thorough 
and  critical  reading  of  the  work. 

It  has  been  regretted  by  a  few  that  the  systematic  names  did  not 
accompany  the  figure  of  the  animal  represented.  One  gentleman  writes 
as  follows : 

"  I  should  have  advised  you  to  give  the  scientific  names  of  all  the 
objects  to  which  you  have  referred.  Many  will  read  your  book,  not 
children,  but  who  are  advanced  enough  to  know  the  names  of  things. 
You  might  have  said,  'Here  is  a  figure  of  the  common  clam  (Mya 
arenaria) ' — if  that  is  the  name  nowadays.  In  this  way  you  give  a  sort 
of  familiar  dictionary  to  students  of  any  age.  More  than  this,  I  believe 
in  people  learning  early  the  scientific  names  of  scientific  objects,  such  as 
worms  and  shells  that  have  no  common  names.  We  talk  nowadays  of 
verbenas,  bouvardias,  gladioli.  Why  not  also  say  Astarte,  Natica,  etc.  ? 
It  is  just  as  easy  to  learn  one  as  another.  Tell  a  child  that  a  shell  is 
a  Modiola,  and  he  learns  the  word  as  quickly  as  mussel." 

It  is  but  fair  to  say  that  the  propriety  of  giving  the  technical  names 
in  this  book  occurred  at  the  outset,  and  the  conclusion  to  leave  them 
out  was  only  arrived  at  after  long  and  careful  deliberation.  It  was  be- 
lieved that  a  very  few  pupils  indeed  would  care  to  know  them,  and  that 
those  who  did  could,  in  most  cases,  find  access  to  some  of  the  books  given 
in  a  list  for  reference  on  the  last  pages  of  this  volume,  wherein  full  de- 
scriptions of  the  species  oftentimes  accompany  their  mention. 

The  main  reason,  however,  in  not  giving  the  technical  names  was, 
that  at  present  they  are  changing  so  rapidly  that  only  the  specialist  in 
each  department  pretends  to  keep  up  with  the  latest  appellation.  An 


x  NOTE  TO  SECOND  EDITION. 

eminent  naturalist  of  Philadelphia  stated  that  in  the  present  condition  of 
nomenclature  the  common  name  of  an  animal  was  oftentimes  more  reli- 
able than  the  scientific  one!  Now,  while  these  rectifications  are  in  many 
cases  essential,  the  names  themselves  are  of  little  consequence  to  those 
who  are  to  learn  the  brief  outlines  of  the  subject,  and  in  this  work  it  is 
desired  to  teach  only  a  few  characters  of  the  snail,  insect,  spider,  worm, 
and  the  like.  The  names  learned  to-day  would,  with  few  exceptions, 
be  of  no  use  ten  years  hence.  More  than  this,  they  would  be  an  abso- 
lute hinderance. 

Gladiolus  remains  gladiolus.  Verlena  has  been  verbena  for  a  long 
time,  and  even  Calla  persists,  when  its  true  name  is  Eichardia.  Mya 
is  still  Mya,  but  Natica,  as  applied  to  the  large  beach-snail,  is  now  Lu- 
natia.  That  teachers  may  fully  appreciate  how  rapidly  these  names 
change,  the  following  examples  are  given :  The  shell,  figured  on  page  23, 
was  known  to  the  author  not  many  years  ago  as  Pyrula  ;  since  then  it 
has  been  called  Fulgar,  Bmycon,  and  now  it  is  called  Sycotycus  !  In 
Gould's  "Invertebrata"  the  author  used  to  study  the  following  species, 
among  others,  under  the  genus  Buccinum,  which  are  given  in  the  first 
column,  the  second  column  indicating  the  new  generic  names  which 
stand  for  the  same  species  at  the  date  of  going  to  press : 

Buccinum  undatum,  Buccinum  undatum. 

obsoletum,  Ilyanassa  obsoleta. 

trivittatum,  Tritia  trivittata. 

plicosum,  Eurosalpinx  cinerea. 

rosaceum,  Astyris  rosacea. 

"         vibex.  Nassa  vibex. 

An  extreme  instance  might  be  given  regarding  one  of  the  most 
common  animals  of  our  coast,  the  sea-urchin.  This  creature  is  still 
known  by  many  as  Echinus  granulatus,  this  name  being  given  within 
twelve  years  by  Agassiz  in  his  "Methods  of  Study  in  Natural  History." 
The  following  list  shows  the  successive  changes  in  its  name  since  that 
time: 

Echinus  granulatus,  .Toxopneustes  drobachiensis, 

Euryechinus  granulatus,      |        Euryechinus  drobachiensis ; 

and,  at  the  date  of  going  to  press,  this  unfortunate  creature  bears  the 
name  of 

STKONGYLOCENTKOTUS  drobachiensis  ! ! ! 

and  yet,  this  little  animal  will  be  known  by  the  name  of  sea-urchin  long 
after  the  time  when  the  systematists  and  their  distracting  nomenclature 
shall  have  been  forgotten.  E.  S.  M. 

SALEM,  MASS.,  October  12,  1875. 


CONTENTS. 


CHAPTER  I. 

PAGE 

FRESH-WATER  SHELLS  .......       1 

Where  to  collect,  1 ;  Empty  or  Dead  Shells,  2;  Parts  of  a  Shell  named,  3;  Forms  of 
Spire,  Dextral,  and  Sinistral  Shells,  4;  Lines  of  Growth,  Growth  of  a  Shell,  5,  6. 


CHAPTER  II. 
FRESH-WATER  SNAILS  ....... 

Where  and  how  to  collect,  7,  8 ;   Live  Shells,  8 ;   Head,  Tentacles,  Foot,  how  they 
breathe,  9, 10;  Operculum,  12;  Gills,  18. 


CHAPTER  III. 
LAND  SNAILS  .  .  .  .  ...  .  .14 

Where  to  collect,  14;  Parts  of  the  Animal,  15, 16;  Tentacles,  Jaw,  17;  Explanation 
about  an  Object  being  enlarged,  18;  Slug,  19;  Eggs  and  Young,  20;  Mantle,  21. 


CHAPTER  IV. 
SEA  SNAILS    .........     21 

Where  to  collect,  22;  Entire  Aperture,  Aperture  Notched  or  Canaliculated,  23;  Si- 
phon, and  its  Uses,  24;  Flesh  and  Animal  Feeders,  25;  Egg-cases  or  Capsules, 
26,  27. 

CHAPTER  V. 

FRESH-WATER  MUSSELS  .  .  .  .  .  .  .27 

Where  found,  27;  Ligament,  Lines  of  Growth,  28;  Regions  of  Mussel,  29;  How 
they  crawl,  30;  Excurrent  and  Incurrent  Orifices,  31;  Siphons.  Mantle.  82;  How- 
Pearls  are  formed,  33;  Internal  Markings  of  Shell,  Hinge,  34;  How  the  Shells 
open  and  Ligament  acts,  36. 


xii  CONTENTS. 

CHAPTER  VI. 

PAGE 

CLAMS,  MUSSELS,  AND  OYSTERS         .  .  .  .  .  .37 

Salt-water  Bivalves,  37;  Parts  of  a  Clam,  Siphons,  Currents  of  Water,  and  how 
they  eat,  38,  89 ;  Ligament,  and  Internal  Markings  of  Shell,  40 ;  Byssus,  42 ; 
Siphonal  Tubes  separate,  44  ;  Oysters,  46  ;  Heart,  Palpi,  Liver,  Gills/Mouth  of 
Oyster,  46,  47 ;  Relations  between  Clams,  Mussels,  and  Snails,  48. 

CHAPTER  VII. 

COLLECTING  INSECTS  .  .  .  .  .  .  .  .49 

How  to  collect  and  arrange,  49 ;  To  make  Insects'  Boxes,  50 ;  To  kill  and  pin  In- 
sects, 51,  52 ;  Where  to  find  Insects,  52,  53. 

CHAPTER  VIII. 

PARTS  OF  AN  INSECT  .  .  .  .  .  .  .53 

True  Insects  or  Hexapods,  Mouth-parts,  55 ;  Antennae,  Eyes,  56,  57 ;  Regions  of 
Body,  58;  Wings,  59,  60;  Position  of  Wings,  61;  How' to  Spread  the  Wings, 
62;  Beetle  spread,  63;  Abdomen,  63,  64. 

CHAPTER  IX. 

PARTS  OF  AN  INSECT  (continued)      .  .  .  .  .  .65 

Parts  of  the  Thorax,  65 ;  Beetle  dissected,  Mouth-parts,  66-69 ;  Appendages  of  thd 
Segments,  70. 

CHAPTER  X. 

GROWTH  OF  INSECTS  .  .  .  .  .  .  .71 

Collecting  Eggs,  Caterpillars,  Chrysalides,  71,  72 ;  Where  to  collect,  73;  Eggs,  74; 
Eaising  Caterpillars,  75,  77;  Chrysalis,  78:  79;  Development  of  Chrysalis,  80; 
Incomplete  Changes,  81 ;  Complete  and  Incomplete  Metamorphosis,  82 ;  Differ- 
ence between  Larva  and  True  Worms,  88-85. 

CHAPTER  XI. 

HABITS  AND  STRUCTURE  OF  INSECTS  .  .  .  .  .85 

Mud-wasp,  85-87;  Mosquito,  88. 

CHAPTER  XII. 

HABITS  AND  STRUCTURE  OF  INSECTS  (continued)       .  .  .  .89 

Young  Grasshopper,  89 ;  Cast-off  Skin  of  Grasshopper,  90 ;  Curious  Accidents,  91 ; 
Air-tubes,  92 ;  How  Insects  breathe,  and  how  some  rest.  93 ;  Sounds  produced 
by  Insects,  94;  Stridulation  of  Grasshopper,  95,  96. 


CONTENTS.  xm 

CHAPTER  XIII. 

PAGE 

HABITS  AND  STRUCTURE  OF  INSECTS  (continued)       .  .  .  .97 

Spittle  Insect,  97,  93 ;  Cicada  or  Seventeen-year  Locust,  99, 100. 

CHAPTER   XIV. 
HABITS  AND  STRUCTURE  OF  INSECTS  (concluded)       .  .  .  .101 

May  Fly  or  Ephemera,  100-103 ;  Caddis  Worm,  104 ;  Gall  Fly,  104,  105 ;  Other 
Galls,  106. 

CHAPTER  XV. 

SPIDERS          .  .  .  .  .  .  .  .  .109 

Parts  of  a  Spider,  110;  Mouth  Parts  and  Eyes,  111 ;  Spinnerets,  112 ;  Legs,  113; 
Habits  of  some,  114;  Net  Building,  115;  Ballooning  Spiders,  116,  117;  Egg 
Cases,  Young  Spiders,  117,  118,  Care  for  the  Youn.',  119, 120. 

CHAPTER  .XVI. 
DADDY-LONG-LEGS,  CENTIPEDES,  AND  MILLIPEDES        .  .  .  .121 

Daddy-long-legs,  121-123  ;  Centipedes,  123,124;  Month,  Parts  of,  125;  Millepedes, 
126;  How  they  lay  their  Eggs,  and  Young,  127;  Comparison  between  Myrio- 
pods  and  Insects,  127, 128 ;  Some  Characters  of  Insects,  Spiders,  and  Myriopods, 

CHAPTER  XVII. 
CRAW-FISH  AND  LOBSTER      .  .  .  .  .  .  .130 

Craw-Fish,  where  found,  130  ;  Begions  of,  131 ;  Mouth  Parts  and  Appendages,  132, 
133 ;  Gills,  134 ;  How  to  arrange  Parts,  135, 136 ;  Moulting,  137  ;  Young  Lob- 
ster, 133. 

CHAPTER  XVm. 

cJnABS,  HERMIT-CRABS,  AND  OTHER  CRUSTACEANS        .  .  .  .138 

Common  Crab,  139;  Eggs,  and  how  they  carry  them,  140;  Fin-like  Legs,  Oyster 
Crab,  141 ;  Hermit  Crab,  142-144;  Fresh-water  Crustaceans,  144;  Sowbug  and 
Eggs,  145, 146;  Eegions  of  Crustacea,  146, 147. 


CHAPTER  XIX. 
BIVALVE  CRUSTACEANS  AND  BARNACLES         .....  147 

Characters  of,  143, 149  ;  Where  found,  150 ;   Appendages,  how  they  secure  their 
Food,  151 ;  Young  Barnacles,  152,  153. 


xiy  CONTENTS. 

CHAPTER  XX. 

PAGE 

WORMS          .........  153 

Angle  Worms,  154  •  How  they  move,  154,  155 ;  Leech,  155  ;  Sea- Worms,  156, 157 ; 
Tube-building  Worms,  159. 

CHAPTER  XXI. 
CONCERNING  NATURAL  GROUPS  .  .  .  .  .  .160 

Characters  of  Articulates,  160  ;  Of  Worms  and  Mollusks,  161 ;  Type  Characters,  161 ; 
Typical  Animals,  162  ;  Systematic  Tables  and  Classification,  163. 

CHAPTER  XXII. 
CHARACTERS  OF  VERTEBRATES  .  .  .  .  .  .163 

External  Characters  of  Salamanders,  163,  164;  Comparison  with  Cat,  165;  Differ- 
ences between  the  two,  166;  Young  Salamander,  166;  Skeleton  of  Cat,  16T; 
Vertebral  Column  and  Spinal  Cord,  169,  170;  Bones  of  the  Ankle  and  Wrist, 
171, 172;  Groups  of  Vertebrates,  178, 174. 

CHAPTER  XXIII. 

BONES  OP  THE  LEG  AND  WING  OF  BIRDS     .  .174 

Importance  of  studying  Young  Forms,  174;  Wing  Bones  of  an  Adult  Bird,  175; 
Embryo  Birds,  and  Wing  Bones  of  same,  176;  Leg  Bones  of  an  Adult  Bird, 
177 ;  Leg  Bones  of  Embryo  Bird,  178 ;  Leg  Bones  of  Young  Toad,  180. 

CHAPTER   XXIV. 

CLASSES  AND  SUB-KINGDOMS  .  .  .  .  .181 

Sub-Kingdom  Mollusca,  Class  Gasteropoda.  181;  Class  Acephala,  182;  Sub-King- 
dom Arthropoda,  Class  Insects,  183 ;  Class  Myriopoda,  184 ;  Class  Aracbnida, 
185 ;  Sub-Kingdom  Vermes,  Class  Annelida,  185 ;  Class  Crustacea,  186 ;  Sub- 
Kingdom  Vertebrata,  187. 

NOTICE  TO  TEACHERS  .  .  .  .  .189 


FIRST    BOOK    OF   ZOOLOGY. 


CHAPTER  I. 

FEESH-WATER    SHELLS. 

FOR  these  lessons,  it  has  been  deemed  best  to  commence 
with  the  shells  of  mollusks,  such  as  snail-shells  and  mussels. 
They  are  better  objects  to  examine  than  insects,  being  more 
simple  in  structure,  and  less  liable  to  be  broken  in  handling. 
When  found  alive,  their  habits  can  be  readily  studied,  as 
they  can  easily  be  kept  alive  in  jars  filled  with  water. 

1.  Let  the  pupils  first  make  a  collection  along  the  shores 
of  some  lake  or  river,  picking  up  all  the  different  kinds  of 
shells  they  meet  with.  The  waves  will  have  thrown  them 
up  on  the  Chores,  or  in  times  of  drought  the  waters  will 
have  left  them  exposed.  Certain  kinds  are  very  small, 
though  they  will  be  found  by  sharp  looking.  Most  of 
the  shells  collected  will  be  empty,  and  these  shells  are 
called  dead  shells,  because  the  soft-bodied  creatures  once 
contained  in  them  have  died  and  decayed,  leaving  the  hard, 
limy  shells.  Some  of  the  shells  collected  may  contain  the 
animal,  and  at  one  time  each  of  them  possessed  a  little  creat- 
ure within,  which  was  the  fabricator  of  the  shell. 


£*"  :    FIRS?  BOOK  OF  ZOOLOGY. 

2.  Remember  that  the  shell  is  not  a  house  built  by  the 
snail,  as  a  wasp  builds  its  nest,  but  the  shell  is  a  part  of  the 
animal,  and  is  connected  to  it  by  certain  muscles,  so  that  it 
cannot  leave  the  shell,  as  many  suppose. 

The  empty,  or  dead,  shells,  are  to  be  studied  first. 

Looking  over  the  shells  collected,  we  shall  find  some  of 
the  following  kinds : 


FIG.  1. — FBESH- WATER  SHELLS. 


A  number  of  fresh-water  mussel-shells,  also,  will  prob- 
ably be  collected. 


FIG.  2.— FEESH-WATEE  MUSSEL-SHELL. 

These  are  to  be  reserved  for  future  examination.     Those 


FRESH-WATER  SHELLS. 


having  a  spiral  turn  or  twist  are  called  snail  shells,  and  are 
to  be  studied  first. 

3.  Let  the  pupils  pick  out  from  their  collections  the 
shells  like  these : 


FIG.  3.— FRESH- WATER  SNAIL-SHELLS. 

The  different  spiral  turns,  or  twists,  are  called  whorls, 
and  the  whorls  together  form  the  spire.  The  opening  into 
the  shell  is  called  the  aperture,  and  the  line  separating  the 
whorls  is  called  the  suture.  The  pointed  end  of  the  spire  is 
called  the  apex. 

apex. 


suture.   ,;.---:"--. 

\ 


body-whorl. 


idiorh  forming  the  spire. 


aperture. 


FIG.  4.— SHELL,  WITH  PARTS  NAMED. 


4  FIRST  BOOK   OF  ZOOLOGY. 

In  some  shells  the  spire  is  elongated  ;  in  others  the  spire 
is  short  /  in  others  still  the  spire  is  depressed  or  flattened. 

FIG.  5. 


SPIBE  ELONGATED.  SUOBT.  FLATTENED. 

4.  If  the  shell  is  held  in  the  hand,  with  the  aperture 
toward  the  holder,  and  the  spire  pointing  upward,  as  in  the 
figures  drawn,  the  aperture  will  be  either  toward  the  right 
hand,  or  toward  the  left  hand.  In  the  figures  already  given, 
the  aperture  is  on  the  right  hand,  and  these  shells  are  called 
dextml,  or  right-handed,  shells. 

Shells  having  the  aperture  on  the  left  hand  when  held  in 
the  way  above  described,  are  called  sinistral,  or  left-handed, 
shells.  Let  the  pupils  here  examine  all  the  shells  they  have 
collected,  holding  each  one  with  the  spire  pointing  upward, 
and  the  aperture  toward  them,  and  separate  the  dextral 
shells  from  the  sinistral  shells.  As  sinistral  shells  are  not 
so  common  as  the  other  kind,  it  may  be  that  none  will  be 
found  in  the  first  collections  made  by  the  pupils.  The  fol- 
lowing is  a  figure  of  a  sinistral  shell : 


FIG.  6.— SINISTRAL  SHELL. 


FRESH-WATER  SHELLS.  5 

5.  If  the  surface  of  the  shell  be  examined  closely,  deli- 
cate lines  running  from  one  suture  to  another  will  be  seen, 
as  in  the  figures  already  given  ;  and,  if  the  shell  be  looked  at 
from  the  side  of  the  aperture,  these  lines  will  be  found  run- 
ning parallel  to  the  edge  of  the  aperture,  or  lip,  as  it  is 
called. 

These  delicate  lines  are  called  lines  of  growth. 


FIG.  7.— SHOWING  LINES  OF  GROWTH  RUNNING  PARALLEL  TO  THE  EDGE  OF  THE  APERTURE. 

The  shell  is  increased  in  size  by  successive  layers  of 
shelly  matter  added  to  the  borders  of  the  aperture.  In  this 
way  the  shell  grows. 

A  clearer  idea  of  the  growth  of  a  shell  may  be  obtained 
by  studying  the  next  figure  (Fig.  8) :  A  representing  in  out- 
line a  young  shell ;  B  representing  the  full-grown  shell  in 
outline ;  and  C  representing  the  same  outline  as  J?,  with  a 
number  of  lines  of  growth  represented  upon  it. 

If  the  shell  were  now  to  continue  its  growth  a  single  half- 
turn,  or  whorl,  the  dotted  lines  would  indicate  the  increased 
stages  it  would  assume  :  a  representing  the  first  increase  in 
size,  J)  the  next  stage,  and  c  the  appearance  of  the  shell  when 
the  additional  half-whorl  has  been  completed. 


FIRST  BOOK  OF  ZOOLOGY. 
BAG 


FIG.  8. — ILLUSTRATING  THE  INCREASE  IN  SIZE  OF  A  SHELL. 

Among  the  lot  of  shells  collected  by  the  pupil,  different- 
sized  ones  will  be  found.'  Now,  if  a  number  of  these,  of 
different  sizes,  can  be  picked  out,  provided  they  belong  to  the 
same  kind,  or  species,  it  will  be  noticed  that  the  apex  of  all 
of  them  will  be  the  same ;  but  that  the  shells  have  increased 
in  size  at  the  aperture,  and  the  aperture  will  be  larger,  and 
the  larger  shells  will  have  more  whorls  than  the  smaller 
shells.  The  following  figures  illustrate  four  different  ages 
of  the  same  species  of  shell : 


Fro.  9.— ILLUSTRATING  DIFFERENT  AGES  OF  THE  SAME  SHELL— THE  LOWER  FIGURES  REPRE- 
SENTING A  VIEW  OF  THE  SHELL  FROM  THE  APEX. 


FRESH-WATER  SNAILS.  7 

6.  The  axis  around  which  the  whorls  revolve  is  called 
the  columella.  This  axis  is  generally  solid,  though  in  many 
shells  it  is  hollow,  as  if  the  whorls  had  turned  around  a 
shaft  which  had  afterward  been  withdrawn.  This  hollow 
axis  looks  like 'an  opening  in  the  base  of  the  shell,  as  in 
the  following  figure : 


FIG.  10.— A  SNAIL-SHELL  BEEN  FEOM  BELOW. 


This  opening  is  called  the  umbilicus.  The  apex  of  the 
shell  is  sometimes  called  the  nucleus,  because  the  shell  com- 
mences to  grow  from  this  point. 


CHAPTER  II. 

FEESH-WATEE    SNAILS. 

7.  THE  pupils  will  now  be  required  to  bring  in  some  live 
snails.  Let  them  examine  bits  of  bark,  chips,  or  branches, 
found  in  ditches,  or  muddy  brooks.  Under  lily-pads  and 
on  the  stems  and  leaves  of  other  aquatic  plants,  and  on 
stones  in  rivers,  snails  of  various  kinds  will  be  found.  A 
dipper  with  the  bottom  perforated,  or  made  into  a  sieve,  and 
attached  to  a  wooden  handle  four  or  five  feet  in  length,  will 
be  found  useful  in  scooping  up  the  sand  or  mud  from  the 


8  FIRST  BOOK  OF  ZOOLOGY. 

bottom  of  rivers  and  ditches.  The  dirt  having  been  sifted 
out,  the  shells  and  other  objects  will  be  left  behind.  The 
dipper  may  be  made  as  in  the  figure. 


Fl«.  11.— DlPPEE  ATTACHED  TO  A   WOODEN   HANDLE  FOR  COLLECTING    SNAILS. 

Shells  collected  with  the  snails  inside,  and  cleaned  for 
the  cabinet,  are  called  live  shells.  They  are  always  more 
fresh  and  perfect  than  dead  shells. 

Having  made  the  collection,  the  snails  should  be  kept 
alive  in  a  wide-mouthed  jar,  or  bottle,  care  being  taken  not 
to  have  more  than  fifteen  or  twenty  in  a  jar  holding  a  quart 
of  water. 

8.  The  pupils  will  have  secured  some  of  the  following 
forms : 


FIG.  12.— FBESH- WATER  SNAILS. 


FRESH-WATER  SNAILS.  9 

The  broad,  creeping  disk  upon  which  the  snail  rests,  and 
by  which  it  retains  its  hold  to  the  glass,  is  called  the  foot. 
The  snail  moves  about,  and  crawls  or  glides  slowly  along,  by 
means  of  the  foot. 

The  two  little  horns  or  feelers,  in  front,  are  called  tenta- 
cles, and,  as  the  snail  moves,  the  tentacles  are  seen  stretched 
out  in  front,  and  occasionally  bending,  as  if  the  creature  were 
feeling  its  way  along.  The  eyes  are  seen  at  the  base  of  the 
tentacles,  as  two  minute  black  dots.  The  mouth  is  between 
the  tentacles,  and  below.  The  part  from  which  the  tenta- 
cles spring  is  called  the  Iwad,  and  the  opposite  end  of  the 
body  is  called  the  tail.  The  surface  upon  which  the  snail 
rests  is  called  the  ventral  or  lower  surface,  and  consequently 
that  portion  of  the  body  which  is  above  is  called  the  dorsal 
surface,  or  back. 

9.  The  pupil,  in  watching  the  habits  of  the  snails 
he  has  collected,  will  notice  some  of  them  crawling  to 
the  surface  of  the  water  to  breathe  air.  The  snail  ac- 
complishes this  by  raising  the  outer  edge  of  the  aperture 
to  the  water's  edge,  and  then  opening  a  little  orifice  in 
the  side,  through  which  the  air  enters  to  the  simple  lung 
within. 

This  orifice  is  on  the  right  side  in  those  snails  having 
dextral  shells,  and  on  the  left  side  in  those  snails  having  sin- 
istral  shells. 

Many  kinds  of  snails  which  live  in  fresh  water  are  called 
air-breathers,  because  they  are  forced  to  come  to  the  surface 
of  the  water  to  breathe  air.  In  doing  so  they  first  expel  a 


10 


FIRST  BOOK  OF  ZOOLOGY. 


bubble  of  air,  which  may  be  seen  escaping  from  the  breathing- 
orifice,  as  in  Fig.  14,  B. 


t      e 


A  view  from  the  back, 
or  dorsal  view. 


tide-meio. 


ventral  view. 
1 1.  Tentacles. 
e  e,  Eyes. 

6,  Breathing-orifice. 
?tt,  Mouth. 


FIG.  13.— A  FRESH-WATER  SNAIL  SEEN  FKOM  ABOVE,  FBOM  THE  SIDE,  AND  FROM  BELOW, 


FRESH-WATER  SNAILS. 


11 


These  fresh-water  air-breathing  snails  may  be  kept  under 
water  for  many  hours  before  life  is  extinct. 


FIG.  11.— Jar  of  water,  in  which  is  contained  a  number  of  species  of  mollusks,  some  of  which 
have  already  been  studied.  Some  of  them  are  near  the  surface,  breathing  air :  A  and  C 
are  taking  in  air ;  B  is  just  expelling  a  bubble  of  air  from  the  lung  ;  D  is  crawling  on 
the  surface  of  the  water ;  E,  <?,  and  /,  are  in  the  act  of  crawling  up,  to  get  a  fresh  supply 
of  air ;  and  Jis  a  water-breather,  having  gills,  but  no  lung. 

10.  Among  the  snails  collected,  there  will  probably  be 

found  some  which  have  a  peculiar  scale  on  the  hinder  part  of 

2  •*•• 


12  FIRST  BOOK  OF  ZOOLOGY. 

the  body.     When  the  snail  crawls,  this  scale  will  be  seen  just 
behind  the  shell,  as  in  Fig.  15,  o. 

This  scale  is  called  the  operculum,  and  when  the  snail 
has  contracted,  or  drawn  within  the  shell,  the  operculuin  is 
seen  to  fit  the  aperture  of  the  shell,  closing  the  shell  as  a 
stopper  closes  the  mouth  of  a  bottle. 


PIG.  15.— SNAIL  WITH  OPEBCULUM.— o,  Operculum ;  e,  Eye;  r,  Eostrum;  #,  Entrance  to  GilK 

Cavity. 

Nearly  all  sea-snails,  that  is,  snails  which  live  in  salt-water, 
and  many  species  of  fresh-water  snails,  and  also  many  snails 
which  live  in  damp  places  on  the  land,  and-  which  are  called 
land  snails,  have  an  operculum. 

When  the  snail  has  retired  within  the  shell,  the  operculum 
will  look  like  this  in  the  aperture  of  the  shell  (Fig.  1G) : 

A  series  of  concentric  lines  will  be  seen  marking  the 
operculum,  and  these  are  the  lines  of  growth,  the  operculum 
growing  around  the  outer  edge  by  successive  additions, 
just  as  the  shell  grows  by  successive  additions  to  its  outer 
margin. 


FRESH- WATER  SNAILS.  13 

The  Western  rivers  teem  with  species  of  snails  having 
opereula. 

11.  If  the  pupil  has  any  of  these  operculated  snails  alive, 


o 
FIG.  16.— APERTURE  OF  SHELL  CLOSED  BY  OPERCULUM,  o. 

he  will  observe  that  they  do  not  come  to  the  surface  to 
breathe  air. 

Instead  of  a  lung,  the  snail  has  a  cavity  containing  an 
organ,  or  part,  called  the  gill,  by  means  of  which  it  is  capa- 
ble of  getting  from  the  water  what  the  air-breathing  snail 
gets  from  the  air,  namely,  oxygen? 

It  will  be  seen  that  the  head  of  the  snail  is  shaped  differ- 
ently in  the  snails  having  an  operculum,  the  mouth  being  at 
the  end  of  a  sort  of  proboscis  or  rostrum.  (See  Fig.  15.) 
The  shells,  too,  are,  as  a  general  thing,  more  solid. 

12.  Thus  far  the  pupils  have  examined  those  snails  which 
live  in  fresh  water.  Some  of  these  were  air-breathers,  and 
came  to  the  surface  of  the  water  at  intervals  to  breathe 
air.  He  has  studied  other  fresh-water  snails  which  did  not 
breathe  air  directly,  but  performed  this  function  by  means  of 

1  If  the  class  is  sufficiently  advanced,  the  teacher  may  here  explain  about 
oxygen  and  what  the  blood  requires,  and  gets  by  respiration. 


14  FIRST   BOOK  OF  ZOOLOGY. 

an  organ  called  the  gill.  And  these  snails  were  operculated, 
that  is,  they  all  possessed  a  little  scale  called  the  operculum, 
which  closed  the  aperture  tightly  when  the  snail  contracted 
within  the  shell. 

He  has  also  learned  that  the  shells  grow  in  size  by  suc- 
cessive additions  of  limy  matter  deposited  around  the  free 
border  of  the  aperture,  and  that  the  delicate  lines  which 
mark  the  surface  of  the  shell,  and  which  run  parallel  to  the 
outer  edge  of  the  aperture,  are  lines  of  accretion,  or  lines  of 
growth. 


CIIAPTEK  III. 

LAND    SNAILS. 

13.  THEEE  are  many  other  species  of  snails  which  live 
out  of  the  water  altogether,  though  they  are  generally  found 
in  damp  places;  and  these  are  called  land  snails,  because 
they  live  on  the  land. 

Let  the  pupils  now  endeavor  to  collect  some  land  snails. 
By  going  to  some  hard-wood  grove  of  maple,  beech,  or  oak, 
and  turning  over  the  layers  of  dead  leaves,  old  rotten  logs, 
or  pieces  of  bark,  they  will  be  sure  to  h'nd  some  specimens 
of  land  snails.  Some  of  them  do  not  grow  larger  than  a 
pin's-head,  others  have  shells  as  large  as  a  hickory-nut. 

They  are  generally  light  brown  in  color,  and  the  smaller 
species  often  have  highly-polished  or  shiny  shells. 

The  spire  is  generally  depressed  or  flattened.     In  many, 


LAND   SNAILS. 


15 


the  border  of  the  aperture  has  a  thickened  white  rim,  or  lip, 
as  it  is  called.  Such  a  collection  having  been  made,  the 
pupil  will  find  among  them  some  of  the  following  kinds  : 


FIG.  17.— THE  SHELLS  OF  LAND  SNAILS. 

14.  The  snail,  as  it  crawls  along,  leaves  a  slimy  trail  af- 
ter it.     This  trail  consists  of  a  fluid,  which  flows  not  only 
from  the  creeping  disk,  but  also  from  the  surface  of  the 
body.      If  the   back   of  the   snail  is   irritated  by  a  sharp- 
pointed  stick,  a  little  whitish  mass  of  this  fluid,  or  mucus, 
will  adhere  to  the  end  of  the  stick. 

By  placing  the  snail  on  a  piece  of  glass,  and  allowing  it 
to  adhere  and  crawl  on  it,  a  good  view  may  be  obtained  of 
the  peculiar  movements  of  this  creeping  disk,  by  looking 
through  the  glass  from  the  other  side. 

The  breathing  aperture  may  be  found  just  within  the 
aperture  of  the  shell,  and  on  the  right  side  in  those  shells 
having  dextral  shells.  This  orifice  will  be  seen  opening  and 
closing  at  intervals.  (See  Fig.  18,  b.) 

15.  In  the  fresh-water  snails  there  are  but  two  tentacles 
upon  the  head.     In  the  land  snails,  with  few  exceptions,  the 


16 


FIRST  BOOK   OF  ZOOLOGY. 


tentacles  are  four  in  number,  a  larger  and  a  smaller  pair. 
The  larger  tentacles  are  called  the  superior  tentacles ;  the 


FIG.  18.— LAND -SNAILS  CRAWLING.— &,  Breathing  Orifice ;  «  t,  Superior  Tentacles ;  i  t,  Infe- 
rior Tentacles;  m.  Mouth. 


smaller  ones,  often  appearing  as  mere  tubercles,  are  called  the 
inferior  tentacles.  (See  Fig.  18,  s  t  and  i  t.)  As  the  snail 
crawls,  the  superior  tentacles  are  seen  in  constant  motion,  as 
if  the  creature  were  feeling  its  way  about  with  them. 

The  eyes,  instead  of  being  at  the  base  of  the  tentacles,  as 
in  the  fresh-water  snails,  are  found  at  the  tip  of  the  superior 
tentacles. 

In  the  land  snails,  with  few  exceptions,  the  tentacles  can 
be  drawn  within  the  head,  and  for  this  reason  they  are  also 
called  retractile  tentacles. 

While  the  snail  is  crawling,  if  the  pupil  touch  the  end 
of  the  tentacle  with  his  finger,  or,  even  if  he  alarm  the  snail 
by  a  sudden  jar,  he  will  see  the  tentacles  quickly  withdraw 
within  the  head.  The  pupil  will  observe  that  the  bulbous 


LAND  SNAILS.  17 

end  containing  the  eye  disappears  first,  as  the  end  of  a  glove- 
finger  disappears,  when  the  hand  is  withdrawn  from  the 
glove,  the  glove  turning  wrong-side  out. 


FIG.  19. -SHOWING  SNAIL  WITH  TENTACLES  RETRACTED,  A;  AND  TENTACLES  PEOTEUDED,  B. 

16.  Something '  may  now  be  learned  as  to  the  way  in 
which  land  snails  eat. 

By  placing  before  the  snail  the  tender  leaves  of  lettuce  or 
cabbage,  the  head  will  be  seen  to  move,  as  little  mouthfuls 
of  the  leaf  are  bitten  off.  The  upper  lip  of  the  mouth  is  fur- 
nished with  a  hardened  piece  called  the  buccal  plate.  It  is 
crescent-shaped,  and,  in  some  species,  the  cutting  edge  is 
notched,  so  that  it  acts  like  an  upper  set  of  teeth,  by  which 
it  bites  off  little  bits  of  the  leaf.  The  floor  of  the  mouth 
is  lined  with  a  membrane  having  upon  it  rows  of  little  points 
which  enable  the  snail  to  rasp  and  grind  its  food.  These  parts 


FIG.  20.— JAW,  OK  BCCCAL  PLATE  OF  A  LAND  SNAIL,  HIGHLY  MAGNIFIED.— (It  can  just  be 
discerned  without  a  microscope.) 

are  so  minute  that  they  can  be  studied  only  by  the  aid  of  a 
microscope.     If  the  pupil  will  watch  his  fresh-water  snail 


18  FIRST  BOOK  OF  ZOOLOGY. 

as  it  crawls  around  on  the  sides  of  the  jar,  he  will  see  at  in- 
tervals the  mouth  open,  and  a  glistening  tongue  appear,  as 
the  snail  laps  up  the  scum  which  forms  upon  the  surface  of 
the  glass. 

NOTE  FOR  TEACHERS  AND  PUPILS. — Let  the  teacher  here  explain  to  the  pupils 
what  is  mean  by  an  object's  being  magnified. 

If  the  teacher  has  a  common  magnifying-glass,  let  each  pupil  in  turn  observe 
its  magnifying  effect,  by  looking  at  a  common  house-fly,  or  the  printed  page  of  a 
book.  If  a  microscope  can  be  shown  to  the  class,  it  will  be  better  still. 

Let  it  be  explained,  also,  what  is  meant  by  an  object's  being  enlarged  two, 
or  three,  or  more  times.  To  be  enlarged  two  or  three  times,  is  to  make  the 
object  two  or  three  times  as  long  as  it  was  before,  and  of  proportional  size. 

In  pictures  of  large  animals,  in  the  picture  of  an  elephant,  for  example,  the 
object  has  often  to  be  reduced  in  size  in  the  figure. 

In  representations  of  very  small  animals,  however,  the  figure  has  to  be  en- 
larged in  order  to  show  parts  plainly  that  could  not  otherwise  be  seen.  Thus 
in  Fig.  24,  b  and  c  are  greatly  enlarged,  to  show  the  little  snail  within  the 

egg- 

17.  In  searching  for  snails,  the  pupil  will  come  across 
snail-like  animals,  which  have  no  coiled  shells  on  their  backs. 
Let  the  pupil  examine  the  under  side  of  damp  boards  or 
plank  walks  in  gardens,  and  he  will  be  sure  to  find  them. 

They  are  very  common  in  old  gardens  in  cities.     These 

FIG.  21.— A  SLUG  CONTRACTED. 

creatures  will  be  found  clinging  to  the  board  or  upon  the 
ground,  and  will  present  this  appearance  (Fig.  21).  Soon, 
however,  they  will  stretch  out  their  tentacles,  and  commence 


LAND  SNAILS.  19 

crawling,  and  then  their  resemblance  to  the  shell-bearing 
snails  will  be  seen  at  once. 

Instead  of  having  a  coiled  shell  into  which  they  can 
retreat  when  alarmed,  they  have  a  little  limy  scale  imbedded 
in  a  portion  of  the  back,  called  the  mantle.  The  breathing- 
orifice  is  on  the  right  side  of  the  body,  and  the  tentacles, 
mouth-parts,  creeping  disk,  and  other  features,  are  quite 
similar  to  the  land  snails  already  studied. 


FIG.  22. — A  NAKED  LAND  SNAIL,  OB  SLUG,  FULLY  EXPANDED. — a.  Mantle ;  ft,  Breathing- 
Orifice. 


18.  On  the  approach  of  winter,  land  snails  bury  them- 
selves in  the  ground,  and  those  that  have  shells  retire  within 
the  shell  as  far  as  possible,  and  close  the  aperture  of  the  shell 
with  a  film  of  the  mucus  which  the  body  secretes  so  abun- 
dantly. In  this  condition  they  remain  dormant  until  re- 
vived by  the  warm  weather  of  spring. 

If  the  pupil  will  collect  a  number  of  snails  in  the  early 
spring,  and  keep  them  confined  in  a  box,  with  earth,  damp 
leaves.,  or  bits  of  rotten  wood  or  bark,  the  snails  in  the  course  of 
a  few  weeks  will  lay  a  number  of  little  eggs.  These  eggs  will 
be  white  and  round,  about  the  size  of  a  pin's-head.  By  care- 
ful tending,  that  is,  by  keeping  the  leaves  slightly  moist,  the 


20  FIRST  BOOK  OF  ZOOLOGY. 

eggs  will  hatch  out  tiny  snails,  and  these  will  attain  half 
their  mature  size  the  first  season. 


b 

FIG.  23. — a,  Eggs  of  Land  Snail ;   &,  Young  Snail  just  hatched ;  c,  Young  Snail  somewhat 
advanced :  &  and  c  are  magnified. 


19.  If  the  pupil  will  also  collect  a  lot  of  fresh-water  air- 
breathing  snails,  and  keep  them  alive,  they  will  deposit  their 
eggs  upon  the  sides  of  the  glass  jar  in  which  they  are  con- 
fined. These  eggs  will  be  oval  in  shape,  and  transparent, 
and  will  be  inclosed  in  a  transparent,  jelly-like  substance.  Fig. 
14,  IT,  represents  the  appearance  of  a  cluster  of  these  eggs. 

Fig.  24  shows  a  cluster  of  eggs  with  the  appearance  of 
two  eggs  highly  magnified,  showing  the  young  snails  as  they 
appear  within  the  egg. 


FIG.  24.— a,  Cluster  of  Eggs  of  a  Fresh- Water  Snail;   &,  c,  Eggs  enlarged,  showing  the 
young  Snails  within  the  Eggs. 

"With  the  aid  of  a  magnifying-glass,  the  eggs  may  be 
watched  from  day  to  day,  and  the  young  snail  can  be  seen  in 
its  various  stages  of  growth. 


LAND  SNAILS.  21 

20.  If  a  land-snail  is  taken  out  of  its  shell  (and  this  can 
be  done  if  boiling  water  be  first  poured  upon  it,  and  then 
with  a  pin  the  animal  can  be  readily  picked  out),  it  will  pre- 
sent this  appearance  (Fig.  25)  : 


FIG.  25.—  LAND  SNAIL  KEMOVED  FBOM  ITS  SHELL.  —  m,  Mantle. 

The  portion  contained  within  the  shell  presents  the 
same  general  appearance  as  the  shell  itself.  A  free  border, 
or  collar,  is  seen  which  corresponds  to  the  aperture  of  the 
shell.  This  border  is  called  the  mantle,  and  is  a  character- 
istic feature  of  all  the  snails  thus  far  studied.  It  is  the  edge 
of  the  mantle  which  deposits  the  successive  layers  of  the 
shell,  and  increases  its  size.  In  the  slug,  there  is  only  the 
limy  scale  ;  this  is  buried  in  the  mantle,  which  is  plainly  seen 
covering  a  portion  of  the  back,  like  a  shield  (Fig.  22,  a). 


CHAPTEK  IY. 

SEA    SNAILS. 


21.  CLASSES  that  live  near  the  sea-coast  may  now  study 
the  marine,  or  salt-water  snails.  These  may  be  collected 
alive  at  low  tide,  upon  rocks,  or  under  the  sea-weed.  By 


22  FIRST  BOOK   OF  ZOOLOGY. 

examining  pools  left  at  low  tide,  many  little  sea  snails  may 
be  seen  creeping  about. 

A  good  place  to  collect  dead  shells  may  be  found  along 
an  exposed  beach.  After  a  violent  storm,  when  the  waves 
have  been  running  high,  a  great  many  animals  are  thrown 
up  from  the  sea,  and  among  them  many  shells  may  be 
secured. 

The  following  will  be  some  of  the  shells  collected  : 


FIG.  26.— COMMON  SEA  SNAILS. 

22.  With  very  few  exceptions,  all  sea  snails  are  water- 
breathers  ;  that  is,  they  are  furnished  with  gills,  instead  of  a 
simple  lung.  Most  of  them  are  operculated. 

In  the  shells  collected  the  pupil  will  find  two  well- 
marked  groups. 

In  the  two  lower  right-hand  figures  of  Fig.  26,  the 
shells  have  an  aperture  with  a  continuous  border ;  that  is, 


SEA   SNAILS.  23 

there  is  no  notch,  or  fold,  in  it.     In  the  three  upper  figures 
there  is  a  notch,  or  fold,  in  the  base  of  the  aperture. 


FIG.  27.— SHELL  SHOWING  LONG  CANAL. 

This  notch  is  called  the  canal,  and  in  some  species  it  is 
very  short,  while  in  other  species  it  is  very  long,  as  in  Fig. 
27. 

The  mantle  of  the  animal  is  prolonged  in  a  fold  which 
occupies  this  canal,  and  is  called  the  siphon.  Through  this 
fold  or  siphon  the  water  finds  access  to  the  gills.  (Fig.  28 
shows  another  species.  The  siphon  is  seen  as  a  fold  of  the 
mantle  running  into  the  canal  of  the  shell.) 

23.  A  very  common  species,  found  in  the  greatest  abun- 
dance from  Maine  to  Florida,  on  mud-flats,  will  give  a  good 


FIRST   BOOK   OF  ZOOLOGY. 


illustration  of  the  uses  of  the  siphon.  In  this  particular 
species,  the  siphon  is  much  longer  than  the  canal,  and,  when 
the  snail  is  crawling,  the  siphon  is  bent  upward.  As  the 


FIG.  28.— A  SEA  SNAIL  SEEN  FEOM  BELOW.— e,  Eye;  m,  Mouth;  «,  Siphon. 

habit  of  this  species  is  to  crawl  along  partly  buried  in  the 
mud,  the  siphon,  projecting  above  the  level  of  the  mud, 
conducts  the  pure  sea- water  to  the  gills  of  the  snail  below. 
Fig.  29  illustrates  the  appearance  of  this  snail : 


ABC 

FIG.  29.— A,  the  Snail  crawling  upon  the  Surface  of  the  Mud ;  £,  the  same  slightly  buried ;  (7, 
the  same  nearly  buried ;  the  Siphon,  «,  is  seen  curved  upward. 


SEA  SNAILS.  35 

Such  shells  are  called  canaliculated  shells. 

The  aperture  of  the  shell  is  said  to  be  entire,  when  it 
does  not  possess  this  notch,  or  canal.  Let  the  pupil  separate 
the  shells  having  the  aperture  entire,  from  those  shells  hav- 
ing a  canal. 

These  differences  in  the  shell,  as  slight  as  they  appear, 
are  accompanied  by  corresponding  differences  in  the  charac- 
ter and  habits  of  the  animal. 

Those  snails  having  the  aperture  of  the  shell  entire  are 
with  few  exceptions  vegetable-feeders,  while  those  having  a 
canal  to  the  shell  are  flesh-feeders.  The  mouth-parts,  and 
opercula,  too,  are  different  in  the  two  groups. 

24.  Other  shells  will  be  found  differing  greatly  in  appear- 
ance from  those  thus  far  studied.  One  of  these  is  repre- 
sented in  the  lower  left-hand  corner  of  Fig.  26. 

Another  species,  called  the  limpet,  looks  like  this  (Fig. 
30): 


FIG.  30. — SHELL  OF  LIMPET. 


These  shells  will  be  found  sticking  with  great  tenacity  to 
the  rocks,  and  some  skill  and  force  will  be  required  to 
remove  them.  This  can  be  done  by  using  the  large  blade 
of  a  pocket-knife,  and  suddenly  scraping  them  from  the  rock. 
If  they  are  then  placed  in  a  saucer  of  water,  with  the  shell 
downward,  the  animal  within  will  be  found  to  have  the 
broad,  creeping  disk,  head,  tentacles,  and  other  parts,  peculiar 
to  the  snails  already  studied. 


26  FIRST  BOOK  t5F  ZOOLOGY. 

25.  In  the  land  snails,  it  was  learned  that  the  eggs 
were  deposited  separately,  while  in  the  air-breathing,  fresh- 
water snails  the  eggs  were  inclosed  in  a  gelatinous  substance. 
Among  the  sea  snails  there  are  many  species  which  inclose 
their  eggs  in  pods,  or  capsules,  as  is  also  the  case  in  the  oper- 
culated  fresh-water  snails.  Sometimes  the  capsules  are 
clustered  together  in  large  masses,  as  in  those  of  the  whelk 
(Kg.  31): 


FIG.  31. —  A  VEET  SMALL  CLUSTER  OF  EGGS  OF  THE  WHELK  DEPOSITED  ON  THE  STEM  OF 
A  LARGE  SEA- WEED.  • 


In  others  they  are  united  in  a  long  string  (Fig.  32). 


A  s  E 

PIG.  82.— J,  a  Portion  of  a  String  of  Egg-Capsules,  from  a  Florida  Species  of  Whelk  similar 
to  Fig.  27 ;  5,  a  single  Capsule  separated,  showing  Outlet,  o,  through  which  the  Young 
escape ;  #,  Stem. 

The  common  cockle  sticks  its  separate  egg-capsules  side 
by  side  upon  the  rock  (Fig.  33). 


FRESH-WATER  MUSSELS.  27 

The  beach-cockle  deposits  its  eggs  in  a  broad  ribbon  of 
sand  cemented  together,  looking  very  much  like  a  deep 
saucer,  with  the  bottom  broken  out,  and  the  side  separated 
(Fig.  34). 


FIG.  33.— EGG-CAPSULES  OF  COMMON  COCKLE.— (A  shell  of  the  animal  which  produces  these 
capsules  is  shown  in  the  upper  central  figure  of  Fig.  26.) 

This  ribbon  is  elastic  when  wet,  and,  if  it  is  held  up  to 
the  light,  the  little  transparent  spaces  for  the  eggs  will  be 
plainly  seen. 


FIG.  84.— EGG-EIBBON  OF  BEACH-COCKLE  (the  shell  of  which  is  shown  in  the  lower 
right-hand  figure  of  Fig.  26). 


CHAPTER  Y. 


FRESH-WATER   MUSSELS. 


26.  LOOKING  over  our  fresh-water  shells  again,  we  find 
many  that  are  known  as  mussels,  or  clams.  These  shells  are 
common  everywhere  along  the  margins  of  brooks,  rivers,  and 
lakes.  The  musk-rats  feed  upon  the  soft  parts  of  the  mus- 


28  FIRST  BOOK  OF  ZOOLOGY. 

sels,  and  the  remains  of  their  feasts  may  he  found  in  piles  of 
mussel-shells  all  along  the  shores  of  certain  lakes. 

The  shell  is  composed  of  two  pieces,  or  valves,  as  they  are 
called.  The  two  valves  are  often  found  united,  and  the 
margin  along  which  they  are  connected  is  called  the  hinge- 
margin^  because  the  shells  hinge  at  this  part,  and  will  open 
and  shut  as  a  door  swings  upon  its  hinges. 

Let  the  pupil  now  examine  a  perfect  fresh-water  mussel, 
that  is,  a  mussel  in  which  the  valves  are  united  in  this  way, 
and  he  will  observe  that  they  are  connected  by  a  brownish 
substance,  which  is  quite  elastic  when  the  shell  is  alive,  but 
becomes  brittle  when  dried.  The  shells  are  held  together  as 
the  covers  of  a  book  are  held  together  by  the  back. 

This  substance  is  called  the  ligament,  and  the  position  of 
this  ligament  will  indicate  the  back,  or  dorsal  region  of  the 
animal. 

27.  On  the  outside  of  the  shell  will  be  seen  fine  lines, 
which  run  nearly  parallel  to  the  outside  margin  of  the  shell. 
These  lines  are  the  lines  of  growth,  and  indicate  the  succes- 
sive stages  of  growth,  or  increase  of  the  shell,  as  in  the  lines 
of  growth  in  the  snail-shell  already  studied,  and,  as  in  the 
snails,  the  growth  takes  place  at  the  margin  of  the  shells. 

The  pupil  may  trace  these  concentric  lines  back,  as  they 
grow  smaller  and  smaller,  till  they  are  found  to  start  from 
one  point  at  the  back  of  the  shell,  and  this  point  is  called 
the  leak  or  umbone.  It  represents  the  starting-point  in  the 
growth  of  the  shell.  In  fresh- water  mussels,  the  umbones 
are  eaten  away  by  some  corrosive  action  of  the  water,  and  the 


FRESH-WATER   MUSSELS. 


early  stages  in  the  growth  of  the  shell  are  usually  destroyed. 
In  very  young  shells,  however,  the  early  stages  can  be  plainly 


seen. 


Back  or  dorsal  region. 


Ventral  region. 

FIG.  35.— A  FRESH-WATEB  MUSSEL. — Z,  Ligament ;  «,  Umbone ;  /,  Foot ;  ex.,  Excurrent 
Orifice;  in.,  Incurrent  Orifice. 

28.  The  ligament  is  always  behind  the  beak,  or  umbone, 
in  fresh-water  mussels,  and  in  nearly  all  bivalve  shells  (so 
called,  because  they  have  two  valves  or  pieces,  while  the 
snail-shells  are  sometimes  called  univalve  shells,  because  they 
have  but  one  valve  or  piece). 

Let  the  pupil  now  hold  a  perfect  mussel-shell  in  -his  hand 
(that  is,  a  mussel  in  which  both  valves  are  together,  and 
united  across  the  back),  with  the  ligament  uppermost,  and  the 
umbone  away  from  him,  or  beyond  the  ligament,  and  the 
valve  on  his  left  hand  is  the  one  which  covers  the  left  side 
of  the  animal,  while  the  valve  on  his  right  hand  covers  the 


30 


FIRST   BOOK  OF  ZOOLOGY. 


right  side  of  the  animal.  The  forward  end  will  be  the  end 
away  from  him,  and  the  hinder  .end  will,  of  course,  be  the 
end  toward  him.  (See  Fig.  35.) 

29.  Let  the  pupils  now  endeavor  to  collect  some  fresh- 
water mussels  alive.  These  may  be  found  partly  buried  in 
the- sand  or  mud  of  rivers  and  lakes.  As  they  crawl  along 
partly  buried  in  this  way,  they  plough  up  the  sand,  leaving  a 
well-marked  furrow  or  groove  behind  them.  Every  boy 
that  goes  in  bathing  is  familiar  with  the  peculiar  furrow  left 
by  the  fresh-water  mussel.  By  following  such  a  furrow,  the 
mussel  that  made  it  will  soon  be  found. 

Fig.  36  represents  the  appearance  of  a  common  fresh- 
water mussel  in  the  act  of  crawling. 


FIG.  36. — SHOWING  POSITION  OP  MUSSEL  WHEN  CRAWLING.—/,  foot  buried  below  the  surface 
of  the  sand  s.  Above  the  line  8  is  supposed  to  be  water,  the  line  representing  the  bottom 
of  a  lake  or  river. 

Having  collected  a  few  in  this  way,  they  may  be  placed 
in  a  large,  shallow  pan  of  water,  and  allowed  to  remain  quiet 
for  a  while.  Gradually  the  shells  will  open  a  little,  and  from 
the  hinder  end  a  curious  fringed  border  appears  ;  on  examin- 


FRESH-WATER   MUSSELS.  31 

ing  this  border,  it  will  soon  be  found  that  the  border  forms 
two  openings  which  lead  into  the  shell. 

Great  care  must  be  taken  not  to  jar  the  dish,  or  the  table 
upon  which  it  rests.  The  slightest  jar  will  cause  the  shells  to 
instantly  close.  If  some  indigo,  or  small  particles  of  dirt,  be 
dropped  near  these  openings,  currents  of  water  will  be  re- 
vealed ;  one  current  pouring  out  of  the  opening  nearest  the 
back,  and  another  current  as  steadily  pouring  in  at  the  other 
opening.  The  opening  into  wrhich  the  current  of  water  is 
passing  is  called  the  incurrent  orifice,  while  the  orifice  from 
which  a  current  of  water  is  passing  is  called  the  excuwent 
orifice.  The  incurrent  orifice  is  sometimes  called  the  respira- 
tory orifice,  because  the  water  is  taken  in  to  supply  the  gills 
which  are  the  breathing  or  respiratory  organs  of  the  mussel, 
and  this  orifice  corresponds  to  the  siphon  in  the  sea  snails 
already  studied.  This  current  of  water,  besides  bathing  the 
gills,  also  carries  in  minute  particles  which  are  floating  in 
the  water,  and  these  particles  are  conducted  to  the  mouth  of 
the  creature,  and  swallowed  as  food.  At  the  opposite  end  of 
the  shell  frem  these  openings,  or  the  forward  end,  a  whitish, 
fleshy  mass  will  be  seen  protruding.  This  is  called  the  foot, 
and  corresponds  to  the  foot  or  creeping  disk  in  the  snails. 
By  means  of  this  foot  the  mussel  crawls  through  the  sand. 

The  mouth  is  above  the  foot,  and  always  concealed  within 
the  shell.  In  Fig.  35  the  foot  is  shown,  and  also  the  excur- 
rent  and  incurrent  orifices,  with  arrows  drawn  to  indicate 
the  direction  of  the  currents  of  water. 

In  some  small  species  of  fresh-water  bivalves,  the  excur- 


32  FIRST  BOOK  OF  ZOOLOGY. 

rent  and  incurrent  orifices  are  prolonged  into  tubes,  and  then 
they  are  called  siphons.  Fig.  37  represents  a  common  spe- 
cies which  the  pupils  may  find  in  muddy  brooks  and  ditches. 
By  using  the  long-handled  dipper  already  described,  some 
specimens  will  probably  be  found.  They  are  quite  small, 
from  the  size  of  a  pea  to  that  of  a  nickel  cent.  The  siphonal 
tubes  are  prominent,  and  the  foot  is  long  and  tongue-shaped, 
and  the  animal  is  very  active  in  crawling  about ;  also  in  Fig. 
14  K  and  Z  represent  two  of  these  small  animals  with  bi- 
valve shells. 


FIG.  37. 


30.  The  foot  of  these  creatures  resembles  in  appearance 
and  action  the  foot  of  a  fresh-water  snail,  only  there  is  no 
mouth  nor  tentacles  in  sight.  These  parts  are  present,  but 
are  never  protruded  beyond  the  edges  of  the  shell. 

When  the  fresh-water  mussels  are  partly  open,  a  fleshy 
border  will  be  seen  just  within  the  edges  of  the  shell,  and 
this  is  the  border  of  the  mantle,  and  corresponds  to  the  same 
parts  described  in  the  snails  ;  the  fringed  membrane  which 
formed  the  openings  at  the  hinder  part  of  the  mussel  is 
simply  a  continuation  of  the  mantle. 

"When  the  shells  are  removed  from  the  animal,  the  mantle 
will  be  found  lining  the  shells,  just  as  the  blank  pages  line 
the  inside  of  a  book-cover.  While  the  edge  of  the  man- 
tle deposits  the  successive  layers,  which  increase  the  size  of 


FRESH-WATER  MUSSELS.  33 

the  shell,  the  entire  surface  of  the  mantle  deposits  the  pearly 
substance  which  lines  the  inner  surface  of  the  shells,  and 
which  is  so  characteristic  of  the  fresh-water  mussels. 

31.  Grains  of  sand,  or  other  particles,  getting  in  between 
the  mantle  and  the  shell,  are  soon  covered  by  layers  of  pearly 
substance  poured  out,  or  secreted  by  the  mantle.  In  this  way 
pearls  are  formed. 

If  pearls  are  broken  open,  a,  centre,  or  nucleus,  will  be 
found,  consisting  of  some  particle  of  dirt  or  sand,  or  some 
substance  which  had  found  its  way  by  accident  between  the 
mantle  and  the  shell,  and  around  which  the  pearly  matter 
has  been  formed  in  successive  layers. 


Fro.  38.— A,  Pearly  Concretions  from  a  Fresh-water  Mussel;    £,  Pearly  Concretions  from 
the  Common  Oyster. 

In  shells  having  a  brilliant,  pearly  lining,  or  nacre,  the 
pearls  obtained  are  oftentimes  very  beautiful,  and  from  cer- 
tain Oriental  species  living  in  the  sea,  called  Avicula,  the 
most  brilliant  pearls  of  commerce  are  obtained.  If,  on  the 
other  hand,  the  nacre  lining  the  shell  is  dull  white,  as  in  the 
common  oyster,  the  pearls  are  dull-colored.  This  kind  of 
pearls  is  often  found  in  oysters. 

The  Chinese  have  long  been  familiar  with  the  art  of 


34  FIRST  BOOK  OF  ZOOLOGY. 

making  artificial  pearls.  By  partly  opening  the  shells  of 
certain  fresh-water  mussels,  and  inserting  little  lead  images, 
or  other  objects,  between  the  mantle  and  the  shell,  the  ob- 
jects soon  become  covered  with  a  natural  layer  of  pearl. 

32.  Let  the  pupils  now  study  the  markings  on  the  inner 
surface  of  the  shells  of  river-mussels.     The  shells  of  these 
creatures  are  called  valves,  and  are  spoken  of  as  right  or 
left  valves,  according  to  whether  they  are  on  the  right  or  left 
side  of  the  animal. 

Certain  ridges  and  prominences  will  be  seen  at  the  hinge, 
and,  when  the  valves  are  carefully  joined,  the  ridges  in  one 
valve  will  correspond  to  grooves  in  the  other  valve.  These 
ridges  are  called  teeth.  The  short  ones,  near  the  beak,  are 
called  cardinal  teeth,  and  the  long  ones  lateral  teeth.  The 
margin  upon  which  they  occur  is  called  the  hinge-margin,  for 
it  is  upon  this  margin  that  the  valves  turn.  (See  Fig.  39.) 

33.  Certain  scars,  or  impressions,  will  be  found  marking 
the  inside  of  the  valves,  and  these  indicate  the  point  of  the 
attachment  of  certain  muscles  to  move  the  valves,  and  to 
enable  the  animal  to  protrude  its  foot,  and  crawl  along. 

These  marks  are  hence  called  muscular  marks,  or  muscu- 
lar impressions,  and  will  be  found  to  correspond  in  the  right 
and  left  valves. 

An  irregular,  round  impression  will  be  found  at  each 
end  of  the  valve,  near  the  hinge-margin.  These  show  where 
the  muscles  are  attached  to  move  and  close  the  valves, 
and  hold  them  firmly  together.  The  muscles  run  directly 
across  from  one  valve  to  the  other ;  and,  to  open  a  live 


FRESH-WATER  MUSSELS. 


35 


mussel,  it  is  necessary  to  pass  a  sharp  blade  between 
the  valves,  and  cut  through  the  muscles,  before  the  valves 
will  open.  These  muscles  are  called  the  adductor  muscles -, 
and  the  scars  or  impressions  on  the  valves  are  called  the 
adductor  muscular  impressions.  Very  close  to  the  adductor 
muscular  impressions  are  seen  smaller  impressions,  and  these 
indicate  where  the  muscles  are  attached  which  move  the 
foot.  These  muscles  are  called  the  pedal  muscles,  and  the 
impressions  are  called  the  pedal  muscular  impressions.  One 
occurs  just  behind  the  anterior  adductor  impression ;  the 
other  will  be  found  just  above,  and  in  front  of  the  posterior 
adductor  impression. 


FIG.  39.— THE  EIGHT  VALVE  OF  A  FRESH- WATEE  MUSSEL.— c,  Cardinal  Teeth ;  I,  Lateral  Tooth ; 
tt,  Ligament ;  a«,  Anterior  Adductor  Impression ;  pa,  Posterior  Adductor  Impression ; 
ap,  Anterior  Pedal  Muscular  Impression  ;  pp,  Posterior  Pedal  Muscular  Impression ; 
p,  Pallial  Line. 

34.  Besides  these  marks,  the  pupil  will  see  a  delicate 

and  slightly  irregular  line  running  from  the  anterior  to  the 
3 


36  FIRST  BOOK   OF  ZOOLOGY. 

posterior  muscular  impression,  just  inside,  and  nearly  parallel 
with  the  lower  margin  of  the  shell.  This  line  is  called  the 
pallial  line,  and  indicates  where  the  mantle  is  attached  to 
the  shell.  It  will  be  observed  that,  when  the  soft  parts  are 
removed  from  the  shell,  the  mantle  adheres  along  this  line. 

The  pupil  may  mark  with  a  pen  the  names  of  all  the 
parts  upon  the  inside  of  a  fresh-water  mussel. 

35.  When  the  mussel  is  opened  by  separating  the  ad- 
ductor muscles  with  a  knife,  the  valves  slowly  open,  and 
after  the  animal  is  removed  the  valves  still  remain  partly 
open,  and,  to  preserve  them  closed,  a  string  has  to  be  tied 
around  them,  and  in  this  condition,  if  the  ligament  is  allowed 
to  dry,  the  valves  will  then  remain  closed.  From  this  it  is 
evident  that  the  ligament  acts  upon  the  valves  to  draw  them 
apart.  To  keep  them  closed,  then,  the  animal  must  continu- 
ally exert  itself  by  contracting  the  adductor  muscles  ;  and  it 
will  be  found  that,  when  these  creatures  are  left  in  the  water, 
undisturbed  for  a  while,  the  muscles  relax,  and  the  valves 
partly  open.  The  ligament  is  elastic,  and  is  stretched  as  it 
were  from  one  valve  to  the  other,  over  the  back.  A  possible 
imitation  of  the  action  might  be  represented  by  partly  open- 
ing the  lids  of  a  book,  and  then  gluing  across  the  back,  from 
one  lid  to  the  other,  a  sheet  of  elastic  rubber.  If,  now,  the 
lids  are  tightly  closed,  the  rubber  is  drawn  out,  or  stretched 
across  the  back,  and,  if  allowed  to  regain  its  elasticity,  the 
lids  are  pulled  apart.  This  experiment  illustrates  the  way  in 
which  the  ligament  acts  in  those  shells  which  have  the  liga- 
ment external. 


CLAMS,   MUSSELS,   AND   OYSTERS. 


37 


CHAPTER  YI. 

CLAMS,    MUSSELS,    AND   OYSTERS. 

36.  CLASSES  having  access  to  salt-water  may  now  collect 
some  bivalves,  as  the  clam,  mussel,  razor-shell,  oyster,  scal- 
lop, and  whatever  species  they  can  find  belonging  to  this 
group.  A  much  greater  variety  of  forms  will  be  found  in 
salt-water  than  in  fresh-water. 

Among  some  of  the  common  species  met  with  will  be 
the  following : 


FIG.  40.— SALT-WATER  BIVALVES. 


In  these  the  pupil  may  trace  out  the  muscular  impres- 
sions within  the  shell,  and  make  out  their  relations  to  the 
impressions  already  described  in  the  fresh-water  mussels. 


38  FIRST  BOOK   OP  ZOOLOGY. 

Many  differences  will  be  observed  in  the  muscular  impres- 
sions, as  well  as  in  the  teeth  and  the  position  of  the  ligament. 

37.  As  the  common  soft-shelled  clam  can  be  readily  pro- 
cured in  the  fish-markets,  it  will  be  well  to  study  this  first. 
A  live  specimen  must  be  selected,  and,  as  the  clam  lives  a 
long  time  after  it  has  been  removed  from  the  water,  there 
will  be  no  difficulty  in  getting  the  proper  specimen.  Upon 
pressing  the  valves  together,  or  touching  the  soft  parts  which 
partly  protrude  from  between  the  valves,  the  creature  will 
show  signs  of  life,  by  drawing  the  shells  closer  together,  and 
this  will  assure  the  pupil  that  the  specimen  is  alive. 

A  large  shallow  dish  may  now  be  filled  with  pure  sea- 
water,  and  in  this  the  clam  may  be  placed.  After  it  has 
remained  there  for  some  time,  the  black  end  of  the  animal, 
which  is  incorrectly  called  the  head,  will  slowly  stretch  out 
from  between  the  shells,  and  the  end,  unfolding,  will  display 
two  openings  fringed  with  little  feelers  (see  Fig.  42).  Into 
one  of  these  openings  the  water  will  be  seen  flowing,  while 
from  the  other  a  current  of  water  will  be  seen  issuing.  And 
these  openings  are  called  the  incurrent  and  excurrent  orifices, 
and  correspond  to  similar  parts  previously  described  in  the 
fresh-water  mussels.  In  the  latter  creature,  the  openings 
just  protruded  beyond  the  edge  of  the  shell.  In  some  very 
small  species  of  fresh-water  bivalves,  one  of  which  was  shown 
in  Fig.  37,  these  openings  were  at  the  end  of  separate  tubes. 
In  the  clam  the  tubes  are  inclosed  in  one  sheath. 

The  clam  can  protrude  this  apparatus  to  a  length  equal- 
ing that  of  the  shell  two  or  three  times.  As  the  clam  lives 


CLAMS,   MUSSELS,  AND  OYSTERS.  39 

buried  at  some  depth  below  the  level  of  the  sand  or  mud  in 
which  it  occurs,  it  requires  this  extension  of  the  openings 
to  reach  the  sea-water  above. 

38.  It  may  be  stated   here,  that   the  current  of  water 
passing  into  the  general  cavity  of  the  shell  not  only  carries 
the  particle  of  food  upon  which  the  animal  subsists,  but  con- 
veys the  pure  sea- water  to  the  gills  by  which  it  breathes, 
the  gills  performing  the  same  function  for  animals  living 
immersed  in  water  as  the  lungs  perform  for  creatures  which 
breathe  air.    All  bivalves  depend  upon  currents  of  water  to 
convey  their  food  to  them. 

While,  in  the  snails,  the  creatures  could  go  in  quest  of 
food,  having  the  power  of  protruding  the  head  from  the 
shell,  and  mouths  furnished  with  means  to  bite  or  rasp 
their  food,  in  the  bivalves  there  is  really  no  head,  they  hav- 
ing only  a  little  opening  directly  under  the  anterior  adductor 
muscle,  which  is  the  mouth,  and  into  which  the  particles  of 
food  are  swept. 

39.  If,  now,  the  clam  is  opened,  the  edges  of  the  mantle 
will  be  found  much  thickened  and  united,  except  a  small  slit 
near  the  front  edge,  through  which  can  be  protruded  a  small, 
tongue-shaped  foot.     Powerful  muscles  will  be  found  at  the 
base  of  the  united  siphons  or  tubes,  which  move  the  siphons 
in  and  out,  and  an  examination  of  the  inside  of  the  shell  will 
show  where  these  muscles  are  attached.     The  pallial  line, 
instead  of  running  directly  from  the  anterior  adductor  im- 
pression to  the  posterior  one,  is  abruptly  curved  back,  and . 
forms  a  sharp  bend,  as  it  turns  again  to  the  posterior  ad- 


40  FIRST  BOOK  OF  ZOOLOGY. 

ductor  impression.  This  mark  is  called  the  sinus,  and,  when 
present,  indicates  the  siphons  to  be  of  considerable  size,  and 
having  large  muscles  to  contract  them. 

Let  these  parts  now  be  marked  with  a  pen  upon  the  shell, 
with  their  names,  as  in  Fig.  41 : 


FIG.  41. — EIGHT  VALVE  OP  A  COMMON  CLAM. — Z,  Ligament;  «a,  Anterior  Adductor 
Impression ;  pa,  Posterior  Adductor  Impression. 

40.  On  opening  the  shell,  a  prominent  tooth  is  seen 
on  one  of  the  valves  near  the  hinge,  while  on  the  other 
valve  there  is  a  corresponding  depression.  "When  the  valves 
are  forcibly  separated,  there  is  left  attached  either  to  the 
tooth,  or  in  the  depression,  a  substance  resembling  dark  glue, 
very  elastic,  and  firmly  attached  to  its  place.  This  is  the 
ligament,  and  is  said  to  be  internal,  because  it  is  within  the 
shell,  and  not  upon  the  outside,  as  in  the  fresh-water  mussel 
already  studied.  When  the  animal  closes  the  shell  by  con- 
tracting the  adductors,  the  ligament  is  compressed,  by  being 
jammed  between  the  prominent  tooth,  and  the  recess  into 
which  it  fits.  When  the  muscles  relax,  the  ligament  expands, 


CLAMS,  MUSSELS,  AND  OYSTERS. 

ex.         in. 


41 


B  A  f 

FIG.  42.— COMMON  CLAM.— A.  showing  Siphons  partly  extended;  in.,  Incurrent  Orifice;  «r., 
Excurrent  Orifice ;  /,  Foot ;  »n,  thickened  border  of  the  Mantle  projecting  beyond  the 
Edge  of  the  Shell ;  B,  Siphons,  greatly  extended.  (The  shell  is  not  drawn,  as  there  was 
no  room  for  it  on  the  page.)  The  excurrent  and  incurrent  orifices  are  more  open  than  in  A. 


42  FIRST  BOOK   OF  ZOOLOGY. 

forcing  the  valves  apart.  The  way  in  which  it  works  might 
be  illustrated  by  placing  a  piece  of  rubber  inside  the  hinge 
of  a  door :  when  the  door  is  closed,  the  rubber  is  squeezed, 
and  the  tendency  would,  of  course,  be  for  the  rubber,  in  ex- 
panding, to  again  push  the  door  open. 

That  it  requires  a  continual  effort  for  the  clam  to  keep 
the  valves  closed,  is  seen  in  the  fact  that  when  these 
creatures  are  allowed  to  remain  out  of  water  for  a  while,  as 
they  are  when  in  the  market,  the  muscles  get  tired,  and, 
relaxing,  the  shells  partly  open.  If,  now,  the  basket  or 
barrel  which  they  are  in  be  suddenly  shaken,  the  clams 
will  as  suddenly  close,  and  a  rustling  sound  is  made,  as  the 
water  is  forced  out  from  the  gill-cavity,  the  water  often 
squirting  out  in  a  stream  from  the  siphonal  openings. 

41.  On  the  rocks  between  high  and  low  water  mark,  and 
adhering  to  the  piles  of  the  wharves,  may  be  found  clusters  of 
mussels  which  are  attached  to  these  places,  and  to  each  other, 
by  little  brown  threads  which  issue  from  between  the  valves 
below.  These  threads  are  made  at  will  by  the  creature,  one 
by  one,  and  are  fastened  to  the  substances  upon  which  they 
rest.  The  threads  are  called  ~byssal-threads,  and,  combined, 
form  the  byssus. 

If  the  pupils  will  collect  a  number  of  these  salt-water 
mussels,  and  place  them  in  a  large  glass  dish  or  bowl  filled 
with  salt-water,  they  may  watch  the  mussels  as  the  creatures 
attach  themselves  to  the  sides  of  the  vessel.  In  the  figure, 
the  byssus  is  seen  like  threads  coming  from  between  the 
valves  below,  with  their  ends  adhering  to  the  stone. 


CLAMS,   MUSSELS,  AND  OYSTERS. 


43 


42.  Fig.  44  represents  an  animal  which  is  often  thrown 
up  on  beaches  along  the  coasts,  after  a  storm,  and  whose  shells 
are  very  common  in  the  debris  thrown  up  by  the  waves. 


FIG.  43. — A  MUSSEL  ATTACHED  TO  A  STONE  BY  ITS  BYSSTJS.— f,  Foot. 

These  shells  are  very  thin  and  delicate,  and  the  valves  are 
strengthened  by  a  thickened  rib  which  runs  from  the  umbone 
toward  the  lower  margin  of  the  valve  within. 

In  this  species  the  siphons  are  united,  the  mantle  projects 
beyond  the  edge  of  the  valves,  and  the  foot  is  flattened  in 
front. 


FIG.  44.— I,  Ligament;  /,  Foot;  m,  Mantle;  «,  Siphons;  ecc.,  Excurrent  Orifice;  in.,  Incurrent 

Orifice. 

Fig.  45  represents  another  animal  which  is  often  abun- 
dant on  the  sea-beach.     In  this  species  the  siphonal  tubes  are 


44  FIRST  BOOK  OF  ZOOLOGY. 

separate,  instead  of  being  united.  This  figure  represents  the 
tubes  only  partly  extended.  They  can  be  thrown  out  to 
twice  the  length  represented  in  the  figure. 

excurrent  siphon. 


incurrent  or  branchial 
siphon. 


FIG.  46. 


Another  species  quite  similar  to  the  above  occurs  on  mud 
flats,  in  company  with  the  common  clam.  If  this  be  col- 
lected alive  and  placed  in  sea-water,  the  creature  will  extend 
its  siphons,  which  are  long  and  separate,  and  bend  them  in 
coils. 

43.  The  pupils  have  now  learned,  among  other  things, 
a  few  features  regarding  the  position  which  certain  bivalves 
occupy  in  their  native  haunts  :  the  fresh-water  mussel  creep- 
ing by  means  of  its  foot  through  the  mud  or  sand  in  which 
it  lives  partly  buried ;  the  salt-water  mussel,  fastened  to 
some  place  by  means  of  its  byssus ;  the  soft-shelled  clam, 
lying  buried  at  some  depth  in  the  mud,  and  extending  its 
siphons  to  conduct  the  pure  sea-water  to  its  gills,  and  food  to 
its  mouth. 

Oysters  differ  considerably  from  the  animals  to  which 
they  are  related,  and  which  have  just  been  studied.  Instead 
of  being  free,  they  grow  attached  by  one  of  their  valves  to 
the  rock  or  to  one  another ;  clusters  of  a  dozen  or  more  in- 
dividuals of  different  sizes  are  found  growing,  attached  to  one 
another,  and  forming  large  masses.  At  any  oyster-market 


CLAMS,   MUSSELS,  AND   OYSTERS.  45 

the  pupil  may  get  these  clusters.  Before  studying  a  speci- 
men, it  is  best  to  clean  the  shell  thoroughly  in  water  by  means 
of  a  coarse  brush. 

44.  Instead  of  having  two  adductor  muscles,  it  has  but 
one  (though  this  muscle,  it  seems,  is  composed  of  two  ele- 
ments). A  single  dark-purple  mark  on  the  inside  of  each 
valve  shows  the  point  of  attachment  of  the  adductor  muscle. 
When  the  oyster  is  opened,  the  mantle  contracts  somewhat, 
so  that  the  edge  of  the  mantle  is  some  way  from  the  margin 
of  the  shell,  as  shown  in  Fig.  47. 

The  left  valve  is  the  larger,  and  is  the  one  that  becomes 
attached  ;  the  right  valve  is  flattened,  and  somewhat  smaller. 
The  mantle  has  its  margins  free ;  that  is,  the  edges  are  not 
united  as  in  the  common  clam,  where  they  are  not  only 
united,  but  greatly  thickened.  Neither  is  the  mantle  pro- 
longed into  siphons  as  in  other  species ;  consequently,  the 
water  flows  in  at  one  portion  of  the  shell,  and  pours  out  of 
another  portion,  not  being  definitely  conducted  by  special 
channels,  as  in  those  forms  heretofore  given.  The  oyster 
can  be  readily  studied,  as  specimens  may  be  got  in  almost 
every  village  in  the  country. 

In  looking  over  canned  specimens,  be  sure  and  pick  out  a 
large  one,  and  one  that  does  not  appear  to  be  mutilated,  as 
they  frequently  are  when  taken  out  of  the  shell  by  the  oys- 
terman,  or  jammed,  as  they  often  are  in  packing. 

To  those  who  can  get  them  alive,  it  is  well  to  have  the 
oysterman  open  the  specimen,  being  sure  that  he  removes 
the  larger  valve,  leaving  the  oyster  attached,  and  resting  in 


46  FIRST  BOOK  OF  ZOOLOGY. 

the  smaller  and  flat  valve,  which  is  the  right  one.  To  ex- 
amine it  properly,  the  specimen  must  be  placed  in  a  deep 
saucer  filled  with  water,  so  as  to  cover  it.  A  number  of 
rinsings  will  remove  the  mucus  with  which  the  oyster  is 
covered,  and  this  will  render  the  specimen  in  better  con- 
dition to  examine.  In  placing  it  under  water  in  this  way, 
the  membranes  float  apart,  and  can  be  more  readily 
studied. 

45.  The  adductor  muscle  is  near  the  middle  of  the  animal. 
It  is  composed  of  two  elements,  one  half  being  of  a  glistening 
white,  and  the  other  half  being  grayish.  Immediately  ad- 
joining the  grayish  portion  of  the  muscle,  a  translucent  space 
is  seen,  and  this  space  contains  the  heart,  composed  of  a  body 
constricted  in  the  centre,  as  if  a  tube  had  been  tied  in  the 
middle  by  a  string.  This  is  the  heart  proper,  and  in  speci- 
mens freshly  opened  the  heart  may  be  seen  to  slowly  pulsate, 
or  beat. 

By  raising  the  mantle,  the  gills  will  be  seen  as  delicate, 
leaf-like  membranes. 

At  the  smaller  end  of  the  oyster,  and  that  portion  which 
comes  next  to  the  beak  or  hinge,  the  mouth  will  be  found 
having  on  each  side  two  delicate  lappets,  which  are  called  the 
palpi.  It  will  be  difficult  to  find  the  mouth,  and  some  pa- 
tience will  be  demanded  in  lifting  the  mantle  and  following 
up  between  the  palpi  to  where  the  mouth  is. 

The  dark  region  just  back  of  the  mouth  contains  the 
stomach  and  liver ;  the  dark  or  blackish  portion,  showing  so 
conspicuously  in  cooked  specimens,  being  the  liver. 


CLAMS,   MUSSELS,  AND   OYSTERS. 


47 


By  referring  to  the  accompanying  figures,  these  parts 
may  be  readily  made  out  : 


FIG.  46.— OYSTER  ATTACHED  BY  LEFT  VALVE  TO  A  STONE. 


FIG.  47.— OYSTER  WITH  THE  LEFT  VALVE  REMOVED.— &,  Heart;   Z,  Ligament;   m,  Position 

of  Mouth. 


46.  The  pupil  will  now  recall  some  characters  in  common 
between  the  snails,  and  the  mussels,  clams,  and  oysters,  thus 
far  studied  in  these  lessons,  namely  :  they  all  have  the  body 
protected  by  a  limy  shell  (except  the  slug),  this  shell  either 
composed  of  one  piece,  as  in  the  snails,  or  of  two  pieces  or 


48 


FIRST  BOOK   OF  ZOOLOGY. 


FIG.  48.— EIGHT  VALVE   OP  AN  OYSTEB,  the  Dark  Semicircular  Mark  near  the  Middle  of 
the  Shell  being  the  Adductor  Muscular  Impression,  the  Pallial  Line  showing  faintly. 


valves,  as  in  the  clams,  mussels,  and  oysters.  All  of  them 
increase  the  size  of  their  shells,  or  grow,  by  the  addition  of 
layers  of  shell-material  to  the  edge  of  the  aperture,  or  the 
margins  of  their  valves,  and  these  layers  are  indicated  by 
delicate  lines  seen  on  the  outside  of  the  shell,  and  called  lines 
of  growth.  They  all,  excepting  the  oyster  and  a  few  other 
forms,  have  the  creeping  disk  or  foot.  In  the  snails,  this  is 
broad  and  flat ;  in  the  mussel  and  clam  the  foot  is  flattened 
sideways,  and  variously  shaped.  In  the  snails,  the  creature 
projects,  with  the  foot,  a  head  furnished  with  feelers,  or  ten- 
tacles, and  the  mouth  is  possessed  of  certain  hard  parts  by 
which  food  can  be  eaten.  In  the  mussels  and  clams  there  is  no 
definite  head,  the  mouth  being  hidden  away  within  the  mantle, 
and  the  creature  projecting,  from  the  forward  end,  only  the 
foot.  In  all  of  these  animals  thus  far  studied  there  is  a  cavity 
within,  containing  the  gills  to  which  water  has  access,  or  else 


COLLECTING  INSECTS.  49 

there  is  a  simple  lung,  as  in  the  air-breathing  snails.  These, 
with  the  cuttle-fishes,  which  we  will  not  consider  here,  be- 
long to  a  branch  of  the  Animal  Kingdom  called  Mollusca. 


CHAPTER  VII. 

COLLECTING     INSECTS. 

47.  THESE  lessons,  as  well  as  the  preceding  ones,  are 
prepared  with  the  understanding  that  the  pupils  shall,  so  far 
as  possible,  make  a  collection  of  the  species  of  animals  stud- 
ied. In  fact,  it  is  a  part  of  the  lesson  to  know  how  and 
where  to  collect,  and  above  all  to  know  how  to  preserve  the 
specimens  collected.  To  enable  the  pupils  to  do  this,  the 
briefest  directions  are  given  for  the  making  of  boxes,  nets, 
etc.,  accompanied  with  the  simplest  methods  of  preserving 
the  collections  made. 

In  many  cases  the  directions  given  are  by  no  means  the 
professional  methods;  thus  the  pupils  are  directed  to  use 
common  pins  for  insects,  while  the  professional  collector  uses 
only  the  true  insect-pins  made  expressly  for  the  purpose,  but 
these  are  oftentimes  difficult  to  procure,  and  are  more  expen- 
sive than  the  common  ones. 

In  commencing  these  lessons,  each  pupil  must  first  be 
provided  with  a  number  of  common  pins,  and  a  box  prop- 
erly arranged  in  which  to  pin  the  insects  collected. 

Some  holiday  afternoon,  or  an  hour  before  school-time 


50 


FIRST  BOOK  OF  ZOOLOGY. 


in  the  morning,  may  be  spent  in  making  the  insect-boxes. 
These  may  be  of  any  convenient  size,  having  a  depth  of  not 
over  two  and  a  half  or  three  inches,  and  furnished  with  a  lid. 
A  shallow  cigar-box  will  answer  the  purpose.  The  bottom 
of  the  box  may  be  lined  with  strips  of  corn-pith,  or  slices  of 
cork,  into  which  the  pins  can  be  easily  stuck.  Large  cork- 
stoppers  will  do,  and  these  may  be  cut  into  lozenge-shaped 
pieces  like  this : 


FIG.  49.— SLICED  COBK  FOR  INSECT-BOX. 


These  pieces  are  to  be  fastened  to  the  bottom  of  the 
box  by  gluing.  If  strips  of  corn-pith  are  used,  they  may  be 
tacked  or  glued  to  the  bottom  of  the  box.  The  box,  when 
finished,  will  look  something  like  this : 


FIG.  50.— INSECT-BOX. 

48.  The  insects,  when  collected,  are  to  be  pinned  to  the 


COLLECTING  INSECTS.  51 

cork  in  the  way  figured,  leaving  the  head  of  the  pin  suffi- 
ciently above  the  insect  to  grasp  with  the  fingers. 

Care  must  be  taken  not  to  have  the  insect  too  far  down 
on  the  pin,  as  its  legs  in  that  case  would  touch  the  bottom  of 
the  box,  and  break  off.  Insects  may  be  killed  by  immersing 
them  in  alcohol  for  a  few  minutes. 


FIG.  51.— INSECT  PINNED 


Butterflies  may  be  killed  by  compressing  the  body  be- 
tween the  thumb  and  forefinger,  as  shown  in  the  figure, 
using  just  force  enough  to  kill,  without'  crushing  them. 
The  fumes  of  benzine,  or  ether,  and  of  certain  poisons,  will 
also  kill  insects,  but  these  substances  should  not  be  suggested 
to  young  pupils,  as  their  use  is  dangerous.  (Teachers  will 
here  use  their  judgment  according  to  the  character  of  their 
classes.)  The  rude  box  and  common  pins  are  offered  sim- 
ply for  experimental  collections.  The  ingenuity  of  a  pupil, 
where  neater  collections  are  desired,  will  readily  secure  bet- 
ter ways  of  making  them. 

49.  The  pupils  may  go  out  in  a  class  in  quest  of  material 


52  FIRST  BOOK   OF  ZOOLOGY. 

for  study,  and  this  is  the  best  way,  as  the  activity  and  suc- 
cess of  one  will  act  as  a  stimulus  to  the  others. 


FIG.  52. 


In  the  country,  the  best  places  to  collect  are  by  the  road- 
sides, or  borders  of  woods  and  groves ;  in  the  gardens,  and 
by  the  fences,  or  along  the  shores  of  lakes  and  brooks,  under 
stones  and  stumps,  the  bark  of  fallen  trees,  or  beneath  the 
layers  of  dead  leaves.  Insects  are  scarce  in  deep  woods,  and 
in  large,  open  tracts  of  pasture-land. 

In  the  cities,  the  parks  and  gardens  will  afford  good 
collecting-grounds,  as  under  plank-walks  and  boards  many 
insects  find  shelter.  Alongside  of  railroad-tracks  the  dis- 
carded sleepers  often  hide  many  a  curious  beetle.  In  short, 


PARTS  OF  AN  INSECT. 


53 


let  the  pupil  peer  under  any  object  large  enough  to  afford 
shelter  to  these  creatures.  By  following  the  furrows  made 
by  a  plow,  certain  kinds  will  surely  be  met  with.  The  pupil 
must  be  urged  to  pick  up  every  thing  that  he  thinks  is  an 
insect,  such  as  grasshoppers,  beetles,  flies,  ants,  spiders,  etc. 
In  a  single  holiday  afternoon  the  pupil  will  have  gath- 
ered some  of  the  following  animals : 


FIG.  53. — SOME  OF  THE  ANIMALS  COLLECTED. 


CHAPTER  YIIL 


PARTS     OF     AN     INSECT 


50.  THE  animals  are  now  to  be  carefully  examined.  Let 
the  pupils  pick  out,  and  arrange  together  in  one  portion  of 
the  box,  all  of  those  which  have  three  pairs  of  legs.  In 


54 


FIRST  BOOK  OF  ZOOLOGY. 


some,  the  legs  will  be  closely  drawn  to  the  body,  but  by 
sharp  looking  they  will  be  found. 

After  studying  these  carefully,  the  pupil  will  observe 
that  those  insects  which  have  three  pairs  of  legs  have  the 
body  divided  into  three  regions,  or  parts,  called  respectively 
the  heady  thorax,  and  abdomen,  and  that,  with  few  excep- 
tions, they  all  have  wings.  Insects  having  these  characters 
are  called  Insects  proper.  They  are  also  called  Hexapods, 
a  word  meaning  six  legs. 

These  are  to  be  studied  first.  The  other  animals  col- 
lected may  be  saved  for  future  study. 

51.  Some  insects  have  the  three  parts  of  the  body  dis- 
tinctly separated,  as  in  the  ants,  flies,  and  wasps.  In  other 
insects  the  parts  of  the  body  are  very  close  together,- so  that 
it  is  difficult  to  distinguish  the  dividing  line,  as  in  certain 
beetles.  Let  the  pupils  examine  each  insect,  and  make  out 
the  head,  thorax,  and  abdomen. 

">  head. 


Insect  with  the  head,  thorax, 
and  abdomen,  distinctly 
separated. 


Insect  with  the  head,  thorax, 
and  abdomen,  close  to- 
gether. 


thorax. 


abdomen. 


abdomen. 


FIG.  54. 


In  the  head,  we  find  the  mouth,  the  eyes,  and  fas  feelers, 
or  antennae. 


PARTS  OF  AN  INSECT. 


55 


The  mouth  is  on  the  under  side  of  the  head,  and  is  sur- 
rounded by  certain  parts  called  mouth-parts.  These  parts 
differ  greatly  in  different  insects. 

52.  In  those  insects  that  chew  their  food,  such  as  the  bee- 
tles and  grasshoppers,  certain  of  the  mouth-parts  act  as  teeth, 
or  jaws,  and,  being  joined  to  the  right  and  left  sides  of  the 
mouth,  move  sideways,  and  not  up  and  down,  as  in  other 
animals.  In  other  insects  some  of  the  mouth-parts  are  very- 
long  and  slender,  so  as  to  form  a  long,  sharp  sting,  as  in  the 
bugs  proper,  so  that  they  use  them  to  suck  the  juices  of 
plants  upon  which  they  feed.  Or,  the  parts  are  again  modi- 
fied in  shape  to  form  a  long,  slender  tube,  by  which  the 
nectar  of  flowers  may  be  sucked,  as  in  the  butterflies. 


antenna. 


mouth-parts. 


antenna. 


mouth-parts.^ 


antenna. 


BUG. 


mouth-parts. 


antenna. 
BEETLE. 

mouth-parts.  \ 


MOTH. 


FLY. 


FIG.  55. — SHOWING  MOTJTH-PARTS  OP  A  FEW  INSECTS. — THE  HEADS  ARE  SEPARATED  FROM 
THE  BODIES,  AND  ARE  FACING  THE  LEFT,  AND  DRAWN  IN  PROFILE  AS  SEEN  FROM  THEIR 
LEFT  SIDES. 


In  the  common  house-fly,  the  mouth-parts  appear  as  a 
proboscis,  a  kind  of  fleshy  appendage  which  is  bent  up  when 
not  in  use.  "When  the  fly  feeds,  the  proboscis  unbends,  and 


56  FIRST  BOOK   OF  ZOOLOGY. 

the  food  is  lapped  up  by  it.     Let  the  pupils  carefully  watch 
a  fly  as  it  feeds  upon  a  bit  of  sugar,  or  as  it  laps  the  hand. 

In  the  butterfly  and  moth  the  pupil  may  uncoil  the  long 
tongue  with  a  pin.  It  resembles  in  appearance  a  watch-spring. 

53.  On  the  front  of  the  head  are  two  horns,  or  feelers, 
called  antennae. 

These  are  variously  jointed,  and  vary  greatly  in  different 
insects. 

In  butterflies,  they  are  generally  long  and  slender,  and 
swollen  at  the  tips,  like  drum-sticks.  Sometimes  they  are 
thread-like^  and  in  others  the  antennae  are  barbed  on  the 
sides,  and  look  like  a  feather,  as  in  certain  moths.  In  some 
beetles  they  are  strongly  jointed.  In  the  common  house-fly, 
they  hang  down  in  front  of  the  head. 

Below  are  given  figures  of  the  left  antenna  of  several 
different  insects  showing  how  different  they  are  in  different 
kinds  of  insects.  The  pupils  might  save  the  antennae  of 
different  insects  and  glue  them  to  a  card,  writing  opposite 
each  one  the  name  of  the  insect,  whether  fly,  beetle,  or  locust. 

54.  On  the  sides  of  the  head  are  round,  smooth  places, 
and  these  are  the  eyes.     They  are  entirely  different  from  the 
eyes  of  most  animals,  for,  when  examined  under  the  micro- 
scope, they  are  seen  to  be  divided  into  little  spaces,  looking 
very  much  like  the  surface  of  honey-comb.     Each  of  these 
little  spaces  represents  a  separate  eye.     Some  insects  have 
hundreds  and  even  thousands  of  these  little  spaces,  or  eyes. 
For  this  reason,  such  kinds  of  eyes  are  called  compound  eyes. 

Under  the  microscope  three  minute  black  dots  may  be 


PARTS  OF  AN   INSECT. 


57 


seen  on  top  of  the  head  between  the  compound  eyes,  and 
these  are  called  simple  eyes. 


A  B          C          D         E  F          G  H 

FIG.  5G.— ANTENNA  OF  VARIOUS  KINDS  OF  INSECTS. 

A,  Fly.  D,  Dragon-fly.  G,  Bug. 

B,  Bee.  E,  Moth.  H,  Beetle. 

C,  Green  Grasshopper.  F,  Butterfly.  7,    Beetle. 

In  many  insects,  as  in  the  dragon-flies  for  example,  the 
compound  eyes  are  very  prominent  and  cover  the  sides  of  the 
head,  enabling  the  insect  to  look  backward  as  well  as  forward. 


FIG.  57. — SHOWING  COMPOUND  AND  SIMPLE  EYES. 
A,  Head  of  Fly,  natural  size. 

JK,  Head  of  Fly  enlarged  eight  times;  c,  compound  eye;  «,  simple  eyes. 
C",  Portion  of  the  surface  of  a  compound  eye  highly  magnified. 


58 


FIRST  BOOK  OF  ZOOLOGY. 


55.  Thus  far  we  have  learned  that  an  insect  proper,  or 
true  insect,  has  the  body  divided  into  three  parts  or  regions, 
called  the  head,  the  thorax,  and  the  abdomen. 

Let  the  pupil  take  a  dead  fly,  and  first  pull  off  carefully 
the  legs  and  wings,  and  afterward  separate  the  head  from 
the  thorax,  and  the  thorax  from  the  abdomen.  Having 
separated  the  parts  in  this  way,  they  may  be  pasted  to  a  card 
in  this  manner,  writing  the  correct  name  beside  each  part,  or 
region,  as  shown  in  Fig.  58. 


FIQ.  58. — CARD,  WITH  EEGIONS  OP  AN  INSECT  GLUED  TO  IT,  AND  MARKED. 

The  principal  parts  of  the  head  are  the  mouth-parts,  com- 
pound eyes,  simple  eyes,  and  antennae. 

56.  In  studying  the  thorax,  the  pupil  may  select  some 
common  insect  (a  large  fly,  or  a  bee,  will  answer  the  pur- 
pose), and  pull  off  the  head  and  abdomen.  A  common 
house-fly  separated  in  this  way  may  be  stuck  upon  a  card. 
By  experimenting  with  a  number  of  insects  in  this  manner, 
the  pupil  will  soon  learn  that  insects  not  only  have  the  body 
divided  into  three  sections,  but- that  the  thorax  invariably 
has  attached  to  it  the  legs  and  wings — the  legs  being  at- 


PARTS  OF  AN  INSECT.  59 

taclied  to   the  under  side  of  the  thorax,  while  the  wings 
are  attached  to  the  upper  side  thereof. 


head,  c 


t/iorax. 


abdomen. 


FIG.  59.— Head,  having  mouth-parts,  antennae,  compound  eyes,  c;  and  simple  eyes, «. 

Thorax,  having  legs  and  wings. 

Abdomen,  never  having  legs  or  wings,  but  having  certain  appendages  at  the  extremity. 

57.  The  wings  of  insects  are  never  more  than  four  in 
number,  and  these  are  arranged  in  two  pairs. 

The  group  of  insects  to  which  the  house-fly  belongs  has 
but  two  wings,  or  a  single  pair,  and  in  this  group  (and  other 
groups  of  insects  as  well)  there  are  some  which  have  no 
wings. 

The  wings  are  very  different  in  shape  and  structure  in 
distinct  kinds  of  insects.  In  the  common  fly  they  are 
quite  small,  and  transparent.  In  the  butterflies  they  are 
large  and  broad,  and  are  covered  with  minute  scales  which 
rub  off  on  the  fingers  like  dust.  In  the  dragon-fly  the 

wings  are  long  and  narrow. 
4 


60 


FIRST  BOOK   OF  ZOOLOGY. 


In  all  these  wings  the  pupil  will  observe  a  net-work  of 
lines,  which  stiffen  the  wing  and  support  the  delicate  mem- 
brane constituting  the  wing,  just  as  the  frame  of  a  kite 
stiffens  and  supports  the  paper  that  is  stretched  upon  it. 
These  lines  are  called  veins,  or  nervures.  To  study  the  vena- 


FIG.  60.— AN  IN-    FIG.  61.— AN  INSECT  WITH 
BECT  WITHOUT  TWO  WlNGS. 

WINGS. 


FIG.  62.— AN  INSECT  WITH  FOUR  WINGS. 


tion  of  the  wings,  is  to  study  the  way  in  which  these  veins 
are  arranged.  It  would  be  well  for  the  pupils  to  stick  upon 
a  card  a  number  of  different  kinds  of  wings,  such  as  those 
of  the  grasshoppers,  beetles,  flies,  wasps,  and  label  them 
accordingly. 

58.  In  many  insects  the  forward  and  hinder  pair  of  wings 
are  of  the  same  nature,  as  in  the  butterflies,  moths,  bees, 
wasps,  and  dragon-flies.  In  other  insects,  however,  the  for- 
ward-wings differ  in  character  from  the  hind-wings.  Thus, 
in  the  grasshopper  the  forward  pair  of  wings  are  more 
dense  in  structure  than  the  hind-wings,  though  the  little 
veins  may  be  seen  closely  crowded  together.  They  differ  as 
well  in  form.  (See  Fig.  64.) 

In  other  insects,  as  in  the  squash-bug,  the  front-wings 


PARTS  OF  AN  INSECT.  61 

have  the  half  nearer  the  body  dense  and  stiff,  while  the 
remaining  portion  of  the  wing  is  very  thin,  or  membranous. 

In  the  beetles  the  front  wings  are  hard  throughout,  and 
in  most  of  them  are  bent  and  moulded  to  the  shape  of  the 
body,  and,  when  closed,  form  a  tight  cover  over  the  hind- 
wings. 

The  forward-wings  of  a  beetle  are  so  unlike  ordinary 
wings,  that  they  are  not  called  wings,  but  are  known  as 
elytra^  a  single  one  being  called  an  elytron. 

59.  When  insects  are  at  rest,  they  generally  bring  their 
wings  into  a  position  different  from  that  taken  by  them  in 
flight.  In  certain  dragon-flies,  however,  the  wings  when 


Butterfly  at  rest  with  wings 
meeting  over  the  back. 


Moth  at  rest  with  the  winps 


Fiu.  63. — INSECTS  AT  BEST. 


at  rest  assume  the  same  position  as  they  do  when  flying.  In 
the  butterfly  the  wings  are  brought  together  over  the  back 
when  at  rest,  while  the  moths,  with  few  exceptions,  rest  them 
sloping  over  the  abdomen,  the  front-wings  covering  the  hinder- 
wings. 


62  FIRST  BOOK  OF  ZOOLOGY. 

In  tlie  grasshopper,  the  front-wings  are  long  and  narrow, 
while  the  hind- wings  are  large  and  broad.  "When  the  grass- 
hopper is  at  rest,  the  hind-wings  are  folded  together  pre- 
cisely like  a  fan,  and,  when  closed,  rest  against  the  sides  of 
the  abdomen,  the  long,  narrow  front-wings  closing  down 
upon  them,  and  covering  them. 

60.  Let  the  pupils  prepare  a  grasshopper,  with  the  wings 
spread  as  in  the  act  of  flying.  A  specimen  which  is  dry  may 
be  moistened  by  wrapping  it  up  in  a  piece  of  wet  cloth,  and 
letting  it  remain  a  day  or  two. 


FIG.  64.— GRASSHOPPER  WITH  THE  WINGS  OF  ONE  SIDE  EXPANDED.—/,  Forward-wing;  h, 

Hinder-wing. 

Having  softened  the  joints  of  the  insect  in  this  way,  it 
may  then  be  pinned  to  a  piece  of  cork,  or  a  pin-cushion, 
and,  the  wings  having  been  stretched,  they  may  be  pinned 
in  this  position,  using  triangular  bits  of  card  through  which 
the  pins  are  passed  to  hold  the  wings  in  place,  as  represented 
in  Fig.  64,  which  shows  a  grasshopper  with  the  wings  on 


PARTS  OF  AN  INSECT. 


63 


one  side  of  the  body  pinned  in  the  way  described.  "When 
the  insect  becomes  perfectly  dry  the  wings  will  remain  in 
the  position  in  which  they  were  pinned. 

A  common  beetle  for  study  should  be  prepared  in  the  same 
way. 

In  the  beetle  the  front-wings  are  very  hard  and  are 
closed  tightly  over  the  hind-wings.  With  a  pin,  or  the 
blade  of  a  knife,  the  upper  or  front  wings  may  be  opened, 
and  beneath  these  will  be  seen  the  hind-wings,  not  folded 
like  a  fan  as  in  the  grasshopper,  but  folded  or  bent  in  the 
middle,  as  the  arm  is  bent  at  the  elbow. 


FIG.  65. — A  BEETLE  WITH  THE  ELYTRON  AND  HIND-WING  OF  THE  EIGHT  SIDE  OPEN,  AND  THE 
ELYTRON  OF  THE  LEFT  SIDE  OPEN  WITH  THE  LEFT  HIND -WING  FOLDED  IN  ITS  NATURAL 
POSITION  WHEN  CLOSED. 

61.   The  abdomen  has  no  wings  or  legs,  but  is  plainly 
marked  with  lines  running  across  the  abdomen  transversely. 


FIG.  66.— ABDOMEN  OF  A  DRAGON-FLY,  SHOWING  RINGS  OR  SEGMENTS. 


64 


FIRST   BOOK  OF  ZOOLOGY. 


These  lines  show  the  separation  of  the  abdomen  into  rings, 
or  segments.  In  insects  with  lengthened  and  slender  ab- 
domens the  segments  are  long,  and  the  abdomen,  when  bent 
or  curved,  bends  at  these  joints,  as  shown  in  Fig.  67. 


FIG.  CT.— INSECT  WITH  A  LONG,  SLENDEE  ABDOMEN. 

If  the  pupil  can  handle  these  parts  delicately  enough, 
he  may  be  able  to  separate  the  abdomen  at  these  joints, 
into  a  series  of  rings,  or  segments,  and  glue  them  on  a  card, 
marked  "  Rings  or  segments  of  the  abdomen"  In  the  grass- 
hoppers the  segments  show  very  plainly.  On  the  hinder 
part  of  the  abdomen  there  are  various  appendages,  some- 
times so  short  as  to  be  scarcely  perceptible,  sometimes  long, 
and  thread-like,  as  in  the  May-fly  (Fig.  98);  again,  in  the 
shape  of  a  sharp  sting,  as  in  the  hornet.  In  the  cricket,  they 
are  quite  long  and  conspicuous.  These  appendages  vary 
greatly  in  different  insects. 


PARTS  OF  AN   INSECT.  55 

CHAPTEE  IX. 

PARTS   OF   AN  INSECT   (CONTINUED). 

62.  THE  pupils  have  learned  that  the  abdomen  is  divided 
into  rings  or  segments,  and  the  division  between  these  seg- 
ments is  plainly  seen  in  most  insects. 

The  thorax  is  divided  in  a  similar  manner,  only  the  lines 
which  divide  the  thorax  are  not  so  plainly  seen. 

The  number  of  segments  in  the  thorax  is  three.  To  the 
first  segment,  the  head  and  first  pair  of  legs  are  attached ;  to 
the  second  segment,  the  second  pair  of  legs  and  the  first  pair 
of  wings  are  attached ;  and  to  the  third  segment,  the  hind 
pair  of  legs,  the  hind  pair  of  wings,  and  the  abdomen,  are 
attached.  The  three  segments  of  the  thorax  have  special 
names :  the  prothorax,  this  being  the  forward  segment,  next 
to  the  head;  mesothorax,  being  the  middle  segment;  and 
metathorax,  being  the  last  segment.  Arranging  these  seg- 
ments with  the  appendages  attached  to  them  in  a  table,  they 
would  appear  as  follows : 

f  (  Has  attached  to  it  the  first  pair  of 

1st  Segment,  Prothorax,     i      ]e<,8 
THE   THORAX   is   COM-  >  TT    ° 

POSED  OF  THBEE  SEG-  J   2d  Segment,  Mesothoraa,    \  Ha8  atta*«?  to  *  **  sec°nd  Pair  of 

|      legs  and  the  first  pair  of  wings. 

3d  Segment,  NetatUora^       Ha8  atta°hed  to  ifc  the  third  Pair  of 
|      legs  and  the  second  pair  of  wings. 

63.  Let  the  pupils  now  endeavor  to  dissect  a  beetle,  care- 
fully separating  the  segments  of  the  thorax,  and,  if  possible, 
the  minute  jaws  and  other  mouth-parts,  and  stick  them  on 


66 


FIRST  BOOK  OF  ZOOLOGY. 


a  large  card,  with  the  names  of  the  different  parts  neatly 
marked  upon  the  card,  as  in  the  accompanying  figure  (Fig. 


compounaeye — "Y^ 


elytron,or first ... 
wing, 
second  leg. 


—  mouth-parts.  ' 


prothoram.    ~\ 


..  mesothorax. 


metalhorax. 


ABDOMEN. 


FIG.  68.— A  COMMON  BKOWN  BEETLE,  WITII  THE  PARTS  SEP  ABATED. 

Having  now  learned  something  about  the  parts  of  an 
insect,  and  having  seen  how  much  these  parts  vary  in  size 
and  appearance  in  different  insects,  the  pupils  are  better  pre- 
pared to  understand  the  surprising  modification  which  the 
mouth-parts  undergo  in  the  different  groups. 

64.  The  parts  of  an  insect's  mouth,  generally  speaking, 
consist  of  an  upper  lip,  called  the  labrum  /  a  pair  of  jaws, 
called  mandibles  /  a  pair  of  smaller  jaws,  called  maxillae,  to 
which  are  attached  little  jointed  feelers,  called  maxillary 


PARTS  OF  AN  INSECT.  67 

palpi  ;  and  a  lower  lip,  called  the  Idbium,  which  represents 
still  another  pair  of  jaws  joined  together;  to  this  joined 
piece,  or  labium,  are  attached  a  pair  of  jointed  feelers,  called 
labial  palpi.  In  Fig.  68  these  parts  are  shown  separated 
from  the  head. 

The  numberless  varieties  of  mouth-parts,  peculiar  to  dif- 
ferent insects,  are  in  reality  made  up  by  modifications  of  the 
parts  above  described.  Thus,  in  one  group  of  insects,  the 
mandibles  are  lengthened  out  into  a  piercing-like  sting,  while 
some  of  the  other  parts  are  reduced  in  size,  or  become  al- 
most obsolete.  In  another  group  the  maxillae  are  greatly 
elongated,  with  their  edges  joined  to  form  a  tube,  while  the 
other  parts  of  the  mouth  are  scarcely  to  be  discerned.  In 
another  group  the  labium  is  greatly  lengthened  to  form  a 
tongue-like  organ  for  lapping  up  food,  while  the  mandibles 
— so  big  and  hard  in  some  insects — are  barely  perceptible, 
and  of  no  use  to  the  insect. 

Not  only,  then,  do  these  parts  assume  different  propor- 
tions and  different  shapes  in  the  different  groups  of  insects, 
but  they  also  vary  greatly  in  being  very  hard  or  very 
soft. 

If  the  pupils  will  examine  the  different  kinds  of  insects', 
wings,  taking  the  front-pair  of  wings  for  example,  they  will 
find  a  marked  difference  between  them,  some  being  very 
large  and  transparent,  as  in  the  dragon-fly,  others  being  hard 
and  opaque,  as  in  the  front  wings  or  elytra  of  a  beetle. 
Compare  the  broad  and  brilliant-colored  wing  of  the  butter- 
fly with  the  straight  and  narrow  fore-wing  of  a  common 


68  FIRST  BOOK  OF  ZOOLOGY. 

grasshopper.    And  yet  these  are  all  wings.    In  a  similar  way 
do  the  mouth-parts  of  an  insect  vary. 

65.  In  the  head  of  a  mosquito,  what  appears  to  be  a 
single  sting,  by  which  the  animal  pierces  the  flesh  and  sucks 
the  blood,  is  in  reality  composed  of  long,  delicate,  thread- 
like parts,  which  represent  the  mandibles,  maxillae,  and  the 
tongue,  or  ligula,  which  represents  a  prolongation  of  the 
labium.  In  the  bugs  the  mouth-parts  are  compacted  into  a 
hard  beak — the  piercer,  so  called,  consisting  of  mandibles, 
maxillae,  and  labium,  the  labrum  being  represented  by  an 
acutely  triangular  piece. 

The  mouth-parts  of  a  beetle  have  already  been  described 
in  general  terms.  They  are  represented  as  separated  from 
the  head  in  Fig.  68,  while  in  Fig.  69  a  side-view  of  another 
beetle  is  given  in  which  the  mandible  shows  very  promi- 
nently, while  the  labrum,  labium,  and  maxillae,  do  not  show 
at  all,  as  they  are  concealed  by  the  other  parts.  The  maxil- 
lary and  labial  palpi  of  one  side  are  seen,  however. 

66.  In  the  butterfly  the  labial  palpus  is  seen  very  large 
and  prominent,  while  the  coiled,  thread-like  tongue  represents 
the  pair  of  maxillae  lengthened  and  joined,  forming  a  long 
elastic  tube  which  can  be  coiled  or  uncoiled  by  the  insect, 
and  through  which  it  sips  the  nectar  of  flowers.  In  the 
mouth-parts  of  a  house-fly  the  parts  are  soft  and  fleshy,  and 
united  together  to  form  a  sort  of  proboscis ;  the  maxillae  are 
minute ;  the  maxillary  palpi  are  present  as  simple  jointed  ap- 
pendages ;  the  mandibles  are  minute,  and  useless ;  while  the 
labium  is  greatly  developed,  having  a  broad  end  which  is 


PARTS   OF  AN  INSECT. 


divided  into  two  lobes  at  the  extremity,  by  means  of  which, 
the  fly  laps  up  its  liquid  food.  The  insides  of  these  lobes 
are  rough,  and  the  irritation  which  flies  produce  when  they 
alight  upon  the  hand  is  caused  by  the  scratching  of  these 
rough  surfaces. 


antenna.  ... 


mandibles,  maxilla,  and  \ 
labium,  united. 


mandible. 

y  palpus. 
labial  palpus. 

antenna. 


SQCASH-BUG. 


BEETLE. 


maxillary  palpus. 

labial  palpus.  — — 
maxilla. - 


antenna. 

maxillary  palpus. 
labium. 


MOTH. 


HOUSE-FLY. 


FIG.  69.— HEAPS  OF  A  FEW  INSECTS  SEEN  FROM  THE  SIDE,  SHOWING  MOUTH- PABTS,  NAMED. 

67.  Much  more  may  be  learned  about  the  mouth-parts  of 
insects,  and  the  pupils  might  attempt  the  separation  of  the 
mouth-parts  of  such  insects  as  the  grasshopper,  beetle,  wasp, 
and  butterfly,  sticking  these  parts,  when  separated,  upon  a 
piece  of  white  card,  as  shown  in  Fig.  68. 


70  FIRST  BOOK  OF  ZOOLOGY. 

It  will  be  advisable,  also,  for  the  pupils  to  utilize  the 
broken  specimens  of  insects  by  selecting  the  wings  of  dif- 
ferent insects  and  gluing  them  upon  a  card,  labeling  each 
one.  Different  kinds  of  antennae  might  be  fastened  upon 
another  card,  and  the  legs  of  some  widely-different  insects 
may  be  arranged  in  the  same  way.  For  example,  let  them 
take  the  hind-pair  of  legs  of  a  grasshopper  and  of  a  water- 
beetle.  It  will  be  instructive  to  observe  how  different  these 
two  kinds  are,  and  how  admirably  one  is  adapted  for  jump- 
ing, while  the  other  is  so  perfectly  fitted  for  a  paddle.  By 
making  comparative  collections  of  this  kind  the  pupils  will 
learn  a  great  deal  regarding  the  structure  of  insects. 

68.  The  pupils  have  thus  far  learned  that  a  true  insect 
has  the  body  divided  into  regions  called  the  head,  thorax,  and 
abdomen ;  that  the  head  bears  the  mouth-parts,  antennae,  and 
eyes.  The  thorax  has  the  legs  and  wings,  while  the  abdomen 
has  only  the  caudal  or  tail  appendages,  and  these  are  not 
often  apparent,  They  have  also  learned  that  the  thorax  is 
made  up  of  three  segments,  not  often  plainly  marked,  while 
the  abdomen  is  composed  of  a  greater  number  of  segments, 
in  most  cases  very  plainly  apparent.  As  each  segment  of 
the  thorax  is  characterized  by  having  attached  to  it  a  pair  of 
appendages,  and  as  the  head  contains  a  number  of  append- 
ages, it  is  believed  by  many  naturalists  that  an  insect's  head 
is  composed  of  a  number  of  segments,  so  closely  merged 
together,  however,  as  not  to  be  distinguished,  except  theo- 
retically. As  naturalists,  however,  differ  in  their  estimate  of 
the  number,  we  will  leave  this  difficult  problem  for  more 
advanced  students  to  study. 


GROWTH  OF  INSECTS. 


71 


CHAPTEK  X. 

GROWTH     OF     INSECTS. 

69.  As  the  study  of  the  growth  of  an  insect,  from  the 
egg  to  maturity,  requires  some  time  and  considerable  care, 
the  different  stages  of  such  growth  may  be  described  and 
taught  with  what  examples  the  pupil  may  be  able  to  collect. 

An  afternoon  may  be  spent  exclusively  in  collecting  the 
following  objects : 


FIG.  70. — EGGS:  A,  Eggs  attached  to  Outside  of  a  Cocoon 
(B  and  C  copied  from  figures  by  C.  V.  Riley). 


FIG.  71.— CATERPILLAR 
AND  GRUB-WORMS. 


FIG.  72.— CHRYSALIDES. 


FIG.  73.— COCOONS  :  A,  showing  Inside  of  Cocoon,  contain- 
ing the  Remains  of  a  Chrysalis-Skin. 


72  FIRST  BOOK  OF  ZOOLOGY. 

In  the  spring  and  fall  the  eggs  of  the  canKer-worm  moth 
may  be  found  in  abundance  on  fences  and  trees  in  cities. 
They  are  very  minute,  and  are  found  in  clusters  arranged 
like  stones  in  a  pavement,  but  with  greater  regularity.  With 
a  sharp  knife  a  shaving  of  wood  may  be  cut  off,  taking  the 
eggs  with  it.  (See  eggs  in  Fig.  77,  5.) 

If  they  are  collected  in  the  spring-time,  little  creatures 
will  hatch  from  them  in  the  course  of  a  few  weeks,  and  these 
may  be  fed  on  the  young  leaves  of  the  elm-tree. 

Eggs  of  other  insects  may  be  found  on  fences,  leaves,  and 
twigs  of  plants ;  also  on  the  leaves  of  the  squash-vine,  and 
other  plants  in  the  garden. 

Certain  eggs  may  be  found  upon  the  twigs  of  apple-trees, 
covered  with  a  shiny  coating,  like  varnish.  For  all  these  ob- 
jects the  pupils  will  have  to  hunt  carefully,  as  only  the  keen- 
est eyes  will  find  them  out. 

70.  Caterpillars  and  grub-worms  are  found  everywhere, 
so  common  indeed  that  the  pupil  has  only  to  examine  the 
fences  as  he  goes  to  school  to  secure  some.  For  certain 
kinds  of  grub-worms,  he  may  dig  in  the  garden,  follow 
the  furrow  made  by  a  plough,  or  tear  the  bark  from 
some  dead  tree,  and  discover  the  specimens  he  is  in  search 
of.  For  chrysalides  and  cocoons  the  pupils  may  be  di- 
rected to  search  on  old  garden-fences,  under  stones  and  dry 
boards. 

Some  chrysalides  will  be  found  hanging  with  the  large  end 
downward,  as  in  Fig.  72 ;  others  will  be  found  suspended 
by  the  small  end,  with  a  delicate  thread  around  the  middle, 


GROWTH   OF  INSECTS. 


73 


holding  the  chrysalis  horizontally,  or  vertically,  against  the 
fence,  as  in  Fig.  80,  C. 

Some  of  them  are  encased  in  a  mesh  of  threads,  which 
may  be  built  against  the  fence,  or  under  the  edges  of  clap- 
boards on  the  sides  of  houses.  And  within  the  cocoons  col- 
lected, the  chrysalides,  or  their  empty  cases,  will  be  found,  as 
in  Fig.  Y3. 


FIG.  74.— PORTION  OF  A  FENCE,  HAVING  UPON  IT,  AMONG  OTHER  THINGS,  EGGS,  CATERPILLARS 
AND  CHRYSALIDES  OF  INSECTS. 


Rich  collecting-places  may  always  be  found  on  old  garden- 
fences  in  cities  and  towns.  Fences  surrounded  by  trees  and 
bushes  will  oftentimes  have  a  great  many  insects  lurking 
under  projecting  edges — caterpillars  climbing  up  the  posts, 


74 


FIRST  BOOK  OF  ZOOLOGY. 


and  chrysalides  attached  to  the  rails  of  the  fence.  Fig.  74 
shows  a  portion  of  a  fence  of  this  kind. 

With  the  eggs,  caterpillars,  and  chrysalides  on  hand,  the 
pupils  are  ready  to  study  the  life-history  of  an  insect. 

71.  Many  animals,  as  fishes,  snakes,  and  birds,  lay  eggs, 
and  from  these  eggs  little  creatures  are  hatched  that  resem- 
ble the  animals  which  laid  the  eggs. 

Insects  also  lay  eggs,  but  from  these  eggs  come  little 
creatures  which  do  not  at  all  resemble  the  insect  that  pro- 
duced them. 

The  different  kinds  of  eggs  collected  by  the  pupils  were 
laid  by  insects  of  different  kinds.  For  example,  if  they  have 
collected  eggs  like  the  following  (Fig.  75),  the  insect  that  laid 
them  was  a  moth,  and  looked  like  Fig.  76. 


FIG.  T6. — INSECT  WHICH  LAID  THE  EGGS  IN 
FIG.  75. 


FIG.  75.— EGGS  LAID  ON  THE 
TWIG  OF  AN  APPLE-TKEE. 


Now,  if  the  pupil  will  keep  these  eggs  in  a  box,  there 
will  hatch  from  them  little  animals  resembling  worms,  very 
tiny  at  first,  but  growing  rapidly  if  supplied  with  appropriate 


GROWTH  OF  INSECTS. 


75 


food.  Insects  generally  lay  their  eggs  in  such  places  that 
the  worm,  or  caterpillar,  coming  from  them  can  easily  find 
access  to  its  proper  food,  and  this  food  in  the  case  of  most 
caterpillars  consists  of  leaves,  or  the  wood,  bark,  or  juices,  of 
plants  and  trees. 

72.  Commencing  with  the  egg,  the  pupil  should  get,  if 
possible,  the  insect  while  in  the  act  of  depositing  her  eggs, 
and  this  will  not  be  difficult  to  do  in  the  case  of  the  canker- 
worm  moth,  whose  caterpillars  commit  such  ravages  upon 
the  elm-trees. 


FIG.  77.— CANKEB-WOBM  MOTH,  EGGS,  AND  WORMS  a,  Female  Canker-worm  Moth  laying 
her  Eggs,  &  ;  c,  Top- View,  and  d,  Side- View  of  an  Egg  magnified ;  e,  Canker-worm  eat- 
ing its  way  out  of  the  Egg, .magnified;  /,  Magnified  View  of  Canker-worm;  g,  Natural 
Size  of  Canker-worm  after  leaving  the  Egg;  h,  Male  Canker-worm  Moth. 

The  female  of  the  canker-worm  moth  has  no  wings. 
They  are  very  common  in  early  spring  and  in  the  fall,  lay- 
ing their  eggs  on  fences.  Fig.  77,  #,  represents  the  female 
moth  depositing  the  eggs ;  J,  the  eggs  being  deposited  upon 
a  chip  which  was  cut  from  a  fence  while  the  female  was  at 
work ;  <?,  represents  a  top  view  of  one  egg  magnified ;  d. 


76  FIRST  BOOK  OF  ZOOLOGY. 

represents  a  side-view  of  the  same  egg ;  e,  represents  another 
egg  with  the  canker-worm  eating  its  way  out ;  /J  represents 
the  canker-worm  highly  magnified,  after  it  has  crawled  out 
from  the  egg ;  g,  shows  the  natural  size  of  the  worm ;  h, 
shows  the  appearance  of  the  male  canker-worm  moth.  The 
female  moth  which  is  laying  the  eggs  differs  from  the 
male  in  having  no  wings. 

Now,  if  fresh  elm-leaves  are  placed  in  the  box  with  the 
worms,  they  will  commence  to  feed  on  them.  The  eggs 
hatch  out  just  as  the  leaves  commence  to  grow,  and  con- 
sequently the  young  worms  have  tender  leaves  to  feed  on 
at  the  outset. 

The  worm  grows  rapidly,  and  after  a  few  weeks  ceases 
feeding,  and,  dropping  to  the  ground,  or  lowering  itself  down 
by  a  thread  spun  from  the  head,  buries  itself  just  below  the 
surface  of  the  ground,  and  there  changes  into  a  chrysalis,  form- 
ing a  rude  cocoon  of  earth  about  it.  At  the  proper  time 
there  comes  from  the  chrysalis  a  male  canker-worm  moth 
with  wings,  or  a  female  canker-worm  moth  without  wings. 

73.  From  the  eggs,  then,  come  worms  or  caterpillars. 
The  worms  or  caterpillars  change  into  chrysalides,  and  some- 
times these  are  inclosed  in  cases  or  cocoons.  From  the  chrys- 
alides come  the  perfect  insects,  similar  to  the  insects  which 
first  laid  the  eggs. 

If  it  is  desired  to  keep  the  caterpillars  alive,  the  pupil 
should  try  to  find  them  when  they  are  feeding,  and  to  ob- 
serve the  kind  of  leaf  they  are  eating,  and  then,  by  giving 
them  fresh  leaves  of  the  same  kind  as  they  need  them,  the 


GROWTH  OF  INSECTS. 


77 


caterpillars  will  grow  rapidly,  and  ultimately  change  into 
chrysalides.  It  is  a  common  thing  to  see  boys  collect  cater- 
pillars and  place  them  in  a  box,  with  grass  to  feed  upon  ;  the 
grass  dries,  and  of  course  becomes  unfit  for  food,  and  even 
if  it  were  fresh  the  caterpillar  would  not  eat  it,  unless  it  were 
its  natural  food.  If  the  pupils  wish  to  raise  caterpillars, 
they  must  be  sure  and  furnish  them  with  the  kind  of  leaf 
they  are  accustomed  to  feed  upon.  It  may  be  an  elm-leaf, 
or  a  cabbage-leaf.  Thus,  there  is  a  common  worm  which 
they  will  find  feeding  on  the  leaves  of  the  Tartarian  honey- 
suckle, as  in  Fig.  78.  To  raise  this  worm,  therefore,  it  is 
necessary  to  furnish  it,  from  time  to  time,  with  the  leaves  of 
this  honeysuckle. 


FlG.  78. — WORM   FEEDING  ON  THE  LEAP  OF  THE  TARTARIAN   HONEYSUCKLE. 

(Copied  from  figure  by  J.  H.  Emerton,  in  Packard's  "  Guide  to  the  Study  of  Insects.") 

In  its  growth,  the  caterpillar  usually  sheds  its  skin  three 
or  four  times. 

After  the  caterpillar  has  become  full-grown,  it  stops  eat- 
ing, and  crawls  about  in  a  restless  manner. 


78  FIRST  BOOK  OF  ZOOLOGY. 

In  the  summer  and  fall,  various  kinds  of  caterpillars  are 
seen  crawling  over  the  sidewalks  and  along  fences.  They 
are  not  now  searching  for  food,  but  are  seeking  an  appro- 
priate place  where  they  can  change  into  the  chrysalis  state. 

From  the  long,  active,  and  often  devastating  caterpillar, 
having  three  pairs  of  small  legs  in  front,  and  other  pairs  of 
blunter  legs  behind,  the  creature  gradually  changes  into  a 
body,  blunt  in  front,  tapering  behind,  with  no  indications  of 
legs,  head,  or  any  of  the  appearances  seen  in  the  caterpillar, 
except  that  the  hinder  part  still  shows  the  division  of  that 
portion  into  rings  or  segments  as  in  the  caterpillar,  and  signs 
of  life  are  still  manifested  by  this  portion  moving  from  side 
to  side,  when  touched.  Many  caterpillars  spin  a  case  or  co- 
coon, as  it  is  called,  in  which  it  incloses  itself  previous  to 
changing  to  a  chrysalis.  The  thread  with  which  they  make 
this  case  issues  from  a  little  tube  in  the  lower  part  of  the 
mouth  or  labium.  Silk  is  made  from  the  thread  composing 
the  silk-worm's  cocoon. 


FIG.  79.— A,  Hinder  Portion  of  Chrysalis-skin  hanging ;  B,  C,  Enlarged  View  of  Hinder  End, 
to  show  the  little  Hooks  by  which  it  hangs. 

74:.  Fig.  79,  Ay  shows  the  hinder  portion  of  a  chrysalis- 
skin,  the  insect  having  escaped  from  it,  and  the  forward  part 


GROWTH  OF  INSECTS.  79 

having  fallen  to  the  ground.  The  chrysalis  is  seen  suspended 
by  the  tail,  and  is  held  there  by  little  hooks  on  the  end  of 
the  tail,  which  become  entangled  in  a  sort  of  web  previously 
made  by  the  caterpillar  ;  B  and  C  represent  different  views 
of  the  chrysalis-tail  enlarged  so  as  to  show  the  hooks.  Pupils 
will  be  sure  to  find  these  empty  chrysalis-skins  attached  un- 
der the  projecting  portions  of  fences. 


FIG.  80.— A,  Caterpillar  getting  ready  to  change  into  a  Chrysalis;  B,  Just  ready  to  shed  its 
Skin  previous  to  changing ;  &,  little  Band  to  hold  it  up ;  (7,  Chrysalis ;  2>,  Butterfly  just 
escaping  from  Chrysalis,  the  Wings  just  being  unfolded. 

Fig.  80  shows  different  stages  of  a  cabbage-worm,  from 
the  worm  stage  to  the  chrysalis  stage :  A,  representing  the 
worm  as  it  assumes  a  position  under  the  projecting  edge  of 
a  fence  ;  B,  after  it  has  supported  itself  round  the  body  by  a 
delicate  thread,  5,  and  attached  itself  by  the  tail  at  the  same 
time ;  and,  (7,  representing  its  complete  chrysalis  condition ; 
Dj  shows  the  butterfly  just  escaping  from  the  chrysalis,  the 
wings  still  being  rumpled.  After  having  escaped  from  the 
chrysalis,  the  butterfly  generally  clings  to  the  empty  case  till 
the  wings  have  expanded  and  dried,  when  it  flies  away. 
Fig.  80  represents  a  cabbage-butterfly  introduced  from  Eu- 


80  FIRST  BOOK  OF  ZOOLOGY. 

rope,  and  now  common  in  certain  parts  of  'New  England.  Its 
wings  are  yellow,  with  two  blackish  spots  on  the  forward 
wing,  and  one  on  the  hinder  wing.  The  chrysalides  of  this 
species  are  very  common  on  fences,  and,  when  collected  in 
the  fall,  may  be  kept  through  the  winter.  During  February 
and  March  the  butterflies  will  come  out,  and  these  may  be 
fed  on  honey  or  sugar  mixed  with  water,  and  in  this  way 
may  be  kept  alive  for  some  time. 

Y5.  The  caterpillar,  then,  having  changed  into  the  chrys- 
alis, remains  in  this  condition  a  few  weeks,  or  even  many 
months,  and  then  the  skin  slowly  cracks  open,  and  out  crawls 
a  creature  no  longer  like  a  caterpillar,  but  having  three  pairs 
of  long,  jointed  legs,  the  body  divided  into  three  very  distinct 
regions — the  head,  thorax,  and  abdomen — the  thorax  having 
wings,  and  the  head  furnished  with  long  antennae,  and  pro- 
vided with  mouth-parts  suitable  for  sipping  nectar,  and  no 
longer  like  the  heavy  jaws  of  the  caterpillar,  suited  only  to 
chewing  coarse  leaves ;  in  short,  a  creature  resembling  the 
insect  which  first  laid  the  eggs  from  which  the  caterpillar 
came. 

76.  Other  names  are  given  to  these  three  stages  of  an 
insect.  The  worm,  or  caterpillar,  is  called  the  larva;  the 
chrysalis  is  called  the  pupa;  while  the  perfect  insect  is  called 
the  imago.  These  terms  are  necessary,  for  without  them 
the  proper  condition  of  an  insect  could  not  be  easily  de- 
scribed. 

Take,  for  example,  the  caterpillar  stage  of  a  butterfly: 
the  same  stage  in  a  common  fly  is  known  by  the  name  of 


GROWTH  OF  INSECTS. 


81 


maggot,  and  in  other  insects  the  same  conditions  are  known 
by  the  name  of  borer,  grub-worm,  and  many  other  terms.  If 
the  pupil  learns  that  all  these  various  names  describe  a  simi- 
lar stage  in  the  lives  of  these  insects,  it  is  much  more  con- 
venient to  have  some  general  term  describing  all  these  stages, 
such  as  larva,  or  larval  stage. 

77.  While  most  insects  pass  through  changes  similar  to 
those  above  described,  there  are  others,  such  as  the  grass- 
hoppers, crickets,  roaches,  and  bugs  proper  (a  group  of  in- 
sects which  includes  the  squash-bug,  chinch-bug,  and  bed- 
bug, all  of  which  have  a  disagreeable  taste  and  odor,  and 
to  which  naturalists  restrict  the  name  of  bug),  which  do  not 
pass  through  a  caterpillar  and  chrysalis  state.  The  young 
hatch  from  the  egg,  and  closely  resemble  the  adult  insect, 


FIG.  81.— DIFFERENT  STAGES  OF  THE  CHINCH-BUG:  a,  Egg;  &,  Newly  -batched  Larva;  c,  Larva 
after  First  Moult;  d,  Larva  after  Second  Moult;  e,  Pupa;  /,  Perfect  Insect. 

[These  figures  are  copied  from  the  Seventh  Annual  Report  of  C.  V.  RILEY, 
State  Entomologist  of  Missouri.] 

except  that  it  has  no  wings,  and  is  of  course  much  smaller 
than  the  parent.  In  its  growth  it  moults  or  sheds  its  skin, 
and  each  moult  reveals  its  wings  more  advanced  in  growth, 


82  FIRST   BOOK   OF  ZOOLOGY. 

till  finally,  on  the  last  moult,  it  attains  the  size  and  features 
of  the  mature  insect.  And  even  in  this  growth,  so  unlike 
the  moth  and  butterfly,  the  terms  larva  and  pupa  are  applied 
to  certain  stages  of  its  history. 

The  foregoing  figure  represents  the  egg  and  successive 
stages  of  the  chinch-bug,  an  insect  which  has  been  so  de- 
structive to  various  crops  in  the  West.  The  figures  are  all 
enlarged ;  the  little  line  at  the  lower  left-hand  side  of  each 
figure  represents  the  natural  size. 

Y8.  Many  insects,  as  the  beetles,  flies,  moths,  butterflies, 
bees,  and  wasps,  pass  through  complete  and  distinct  changes 
from  their  early  condition  to  maturity,  as  above  described. 
Other  insects,  as  the  grasshoppers,  crickets,  roaches,  and 
bugs,  hatch  out  from  the  egg,  as  little  six-footed  insects, 
and  not  as  worms,  and  in  their  growth  do  not  pass  through 
an  inactive  pupa  or  chrysalis  stage,  but  slowly  acquire  wings, 
and  ultimately  attain  full  growth  as  above  stated.  Hence 
these  changes  are  not  so  completely  defined  as  the  changes  in 
the  insects  first  mentioned.  For  this  reason  the  term  com- 
plete metamorphosis  is  used  to  define  the  mode  of  growth  of 
the  beetles,  flies,  and  other  insects  having  a  similar  mode  of 
growth;  while  the  term  incomplete  metamorphosis  defines 
the  mode  of  growth  of  the  grasshoppers,  crickets,  and  others. 

79.  Many  of  the  larvae  of  insects  look  like  worms — so 
much  so,  indeed,  that  they  are  commonly  called  worms,  such 
as  cut-worms,  canker-worms,  currant-worms,  and  the  like. 
The  pupils  have  learned  that  these  are  not  true  worms,  but 
only  the  larval  condition  of  certain  insects. 


GROWTH  OF   INSECTS.  83 

True  worms,  however,  never  change  into  any  thing  else. 
Such,  for  example,  is  the  earthworm,  hair-worm,  and  leech, 
and  worms  which  live  in  the  sea. 


FIG.  82.— EAETIIWOBH. 


FIG.  83.— MABINE  WOEM. 

These  worms,  and  other  true  worms,  generally  speaking, 
have  the  body  divided  into  a  great  many  segments  or  rings, 
as  in  the  earthworm.  In  the  larvae  of  insects,  on  the  con- 
trary, the  segments  are  limited  in  number.  "With  few  ex- 
ceptions the  larvae  of  insects  have  legs,  and  these  legs  in  the 
fore-part  of  the  body  are  jointed.  In  worms,  jointed  legs  do 
not  occur.  The  jointed  legs  of  the  larvae  number  three  pairs, 
and  are  on  the  three  successive  rings  back  of  the  head,  and 
consequently  correspond  to  the  three  pairs  of  legs  in  the  adult 
insect. 

In  certain  larvae  other  legs  occur,  but  these  are  not  jointed, 

though  often  having  special  structures  at  their  extremities, 
5 


84  FIRST  BOOK  OF  ZOOLOGY. 

by  which  they  are  enabled  to  cling.     These  are  called 
legs,  or  false  legs. 

It  would  be  well  for  the  pupils  to  collect  some  leeches  and 
earthworms,  and,  if  they  live  near  the  sea- shore,  a  few  worms 
may  be  collected  under  stones  at  low  tide. 

Having  collected  these,  let  the  pupils  compare  them  with 
the  larvae  of  insects. 

As  the  larva  of  an  insect  comes  from  the  egg,  it  has  its 
full  number  of  segments  at  the  outset.  In  the  larva  of  a 
butterfly,  for  example,  there  may  be  counted,  besides  the  head, 
twelve  segments  or  rings,  and  this  number  does  not  increase 
as  the  creature  grows,  but  remains  constant ;  and,  as  we  have 
already  learned,  the  creature  does  not  long  remain  in  its 
worm-like  stage,  but  assumes  other  conditions,  ultimately  be- 
coming a  creature  unlike,  in  form  and  habits,  the  larval  con- 
dition in  which  it  spent  a  portion  of  its  life. 

80.  The  true  worm,  on  the  contrary,  comes  from  the  egg 
with  a  very  limited  number  of  segments,  and  as  it  grows 
new  segments  are  formed,  till  in  some  worms  as  many  as 
four  or  five  hundred  segments  are  developed  before  the  ani- 
mal has  attained  mature  proportions,  and  in  this  condition 
it  remains ;  that  is,  it  is  complete,  never  changing  or  passing 
through  larval  or  pupal  stages  to  develop  into  something 
quite  unlike  the  worm. 

Briefly,  then,  a  larva  may  be  distinguished  from  a  true 
worm  generally  by  its  limited  number  of  segments,  and,  when 
supplied  with  legs,  having  three  pairs  of  jointed  ones  on 
the  anterior  rings  of  the  body. 


HABITS   AND   STRUCTURE   OF   INSECTS.  85 

With  few  exceptions  worms  live  in  the  water,  and  even 
those  which  live  on  the  land  are  limited  to  damp  earth  or 
moist  places.  While  the  larvae  of  insects  are  in  many  cases 
aquatic  in  their  habits,  and  breathe  or  respire  by  means  of 
gills,  the  larger  number  live  on  the  land,  feeding  on  leaves, 
wood,  and  substances  of  a  similar  nature,  and  are  air- 
breathers. 


CHAPTEE  XL 

HABITS     AND     STRUCTURE     OF    INSECTS. 

81.  LET  the  pupils  now  endeavor  to  study  the  habits  of 
certain  insects  by  direct  observation.  The  following  sketches 
are  given  as  aids  to  the  pupils  in  making  independent  obser- 
vations on  special  insects. 

Most  insects  make  no  provision  for  the  larvae,  but  leave 
them  to  take  care  of  themselves,  though  usually  the  egg  is 
deposited  where  the  larva  coming  from  it  may  find  proper 
food  at  hand. 

Other  insects  prepare  cells  or  cavities  in  which  they  de- 
posit their  eggs,  just  as  a  bird  builds  a  nest  to  hold  its  eggs. 
Certain  insects,  in  preparing  these  cells,  also  lay  up  a  store  of 
food  ready  for  the  larva  when  it  shall  have  hatched  from  the 
egg.  Such  is  the  case  with  the  common  mud-wasp.  This 
insect  makes  a  number  of  little  chambers  of  mud,  generally 
sticking  them  to  the  sides  of  a  wall,  or  to  the  ceilings  of  sheds, 
barns,  and  attics.  These  pellets  of  mud  are  seen  firmly  plas- 


86  FIRST  BOOK  OF  ZOOLOGY. 

tered  to  the  wall,  rough  and  irregular  in  appearance,  and  at 
first  sight  might  be  mistaken  for  the  work  of  some  mis- 
chievous boy. 


FIG.  84.— A  MUD- WASP'S  NEST,  HAVING  Two  CELLS. 

Fig.  84  represents  their  general  appearance,  for,  rough 
as  they  appear,  on  close  examination  they  are  seen  to  be 
constructed  very  systematically  —  the  soft  clay  of  which 
they  are  built  being  laid  on  in  alternate  layers,  looking 
something  like  "a  braid ;  while  the  upper  portion,  being  built 
of  looser  and  coarser  material,  is  put  on  in  irregular  lumps. 
With  a  thin-bladed  knife  these  mud-cells  may  be  scraped  off, 
and  sometimes  can  be  pulled  away  with  the  fingers.  Upon 
opening  them  they  will  be  found  either  filled  with  little 
spiders,  or  containing  yellow-colored  larvae,  pupae  in  brown 
skins,  or  wasps.  Their  histoiy  is  as  follows : 

82.  When  the  rnother-wasp  gets  ready  to  lay  her  eggs, 
she  first  builds  these  curious  nests  of  mud,  which  she  collects 
from  the  streets,  or  by  the  sides  of  brooks  in  clayey  soil.  Hav- 
ing finished  one  cell,  she  deposits  therein  an  egg,  and  then 
collects  a  number  of  small  spiders  with  which  she  completely 
fills  the  cell.  After  this  is  done  she  closes  up  the  top  of  the 


HABITS   AND  STRUCTURE   OF 


87 


cell  with  looser  mud.  Thus  she  proceeds,  constructing  cell 
after  cell,  going  through  the  same  manoeuvres  with  each  one. 
It  has  been  observed  that  the  wasp  stings  the  spiders  so 
as  to  paralyze,  but  not  to  kill  them.  Hence  they  remain 
alive  but  cannot  struggle,  and  when  the  egg  hatches,  the 
little  larva  coming  from  it  finds  in  these  spiders  a  store 
of  food  on  which  to  feed.  These  are  gradually  eaten,  and 
thus  room  is  made  for  the  rapidly-growing  larva  which,  hav- 
ing eaten  all  the  spiders,  passes  into  its  pupa  state  surrounded 
by  its  brown  chrysalis  case,  and  finally  emerges  a  perfect 
wasp,  when  it  softens  the  mud-walls  of  its  nest,  by  a  fluid 
poured  from  its  mouth,  and  gnaws  its  way  out. 


FIG.  85. — SHOWING  A  NEST  OF  FOUR  CELLS  CUT  OPEN  :  a,  representing1  a  Cell  with  the  Egg 
at  the  Bottom,  and  the  remaining  Space  filled  with  Spiders ;  &,  the  Larva  full-grown, 
after  having  consumed  all  the  Spiders;  c,  the  Pupa;  and  d,  the  Imago,  or  Perfect 
Wasp,  ready  to  come  out. 


Fig.  51  shows  one  of  these  mud-wasps  pinned. 

The  pupils  may  collect  these  nests  or  cells  in  April  or 
May,  and  by  June  the  wasps  will  be  ready  to  come  out.  If 
collected  soon  after  they  are  made,  the  eggs  may  be  found ;  if 


88 


FIRST  BOOK  OF  ZOOLOGY. 


a  little  later,  the  larva  will  be  found  feeding  on  the  spiders ; 
and,  still  later,  the  full-grown  larvae  and  pupse  appear. 

In  collecting  for  the  cabinet,  one  nest  should  be  cut  open 
to  show  the  cells  and  their  contents. 

83.  The  mosquito  deposits  her  eggs  on  the  surface  of  the 
water,  sticking  them  together  in  such  a  way  as  to  form  a 
raft.  From  these  eggs  little  black  creatures  hatch,  which 
swim  about  with  a  quick,  jerking  motion.  In  this  condition 
they  represent  the  larvae.  If  the  pupils  will  examine  pools 
and  ditches,  or  even  the  tubs  and  barrels  of  water  which  often 
stand  about  farm-houses,  they  will  be  very  sure  to  find  some 
of  these  animals.  They  are  small  and  black,  and  by  their 


A  S 

FIG.  86.— A,  Larva;  and  B,  Pupa  of  a  Mosquito;  c,  Line  showing  Natural  Size  of  Larva;  d, 
representing  Water-Line.— The  larva  is  seen  with  the  hinder  end  of  the  body  just  pro- 
jecting above  the  surface  of  the  water,  so  that  the  air  may  enter  through  the  little  tube. 
The  pupa  is  seen  with  the  back  just  level  with  the  surface  of  the  water,  and  through  the 
two  tubes,  on  the  back  of  the  thorax,  the  air  is  being  admitted  to  the  body. 

rapid,  jerking  motion  cannot  be  mistaken.  A  number  may 
be  collected  and  placed  in  a  jar  of  water,  where  all  their 
changes,  from  the  larval  to  the  perfect  state,  may  be  watched. 
They  will  be  seen  coming  to  the  surface  of  the  water  for  air, 


HABITS  AND   STRUCTURE   OF  INSECTS.  89 

which  they  breathe  in  through  openings  in  the  hinder  part 
of  the  body.  Changes  soon  take  place  by  which  they  as- 
sume the  pupa  state,  and  at  this  time  they  no  longer  breathe 
through  the  hinder  portion  of  the  body,  but  through  two 
tubes  on  the  back  of  the  thorax.  Finally,  the  pupal  skin  cracks 
open,  and  out  crawls  the  perfect  mosquito,  for  a  while  rest- 
ing on  the  empty  pupal  case  which  floats  in  the  water  like 
a  raft,  and  the  insect  remains  supported  in  this  way  till  the 
wings  become  fully  expanded  and  dry,  when  it  flies  away. 


CHAPTEK  XII. 

HABITS    AND    STRUCTURE   OF    INSECTS    (CONTINUED). 

84.  IN  certain  groups  of  insects  the  young  hatches  from 
the  egg,  not  as  a  caterpillar,  but  as  a  little  insect  having  the 
body  divided  into  three  regions,  possessing  three  pairs  of 
jointed  legs,  and  looking  very  much  like  the  mature  insect, 
except  that  it  is  very  much  smaller  and  has  no  wings. 


FIG.  87. — YOUNG  GRASSHOPPEB. — w,  Wing  just  appearing. 

In  the  grasshopper,  for  example,  the  animal  does  not  pass 
through  a  series  of  abrupt  changes,  but  the  creature  comes 
from  the  egg  with  the  general  proportion  of  the  adult  insect, 


90 


FIRST  BOOK   OF  ZOOLOGY. 


save  that  it  has  no  wings,  these  growing  gradually  as  the 
creature  increases  in  age.  Fig.  87  represents  a  young  grass- 
hopper with  the  wings  just  appearing.  At  intervals,  the  in- 
sect sheds  its  skin,  or  moults,  the  wings  continually  increas- 
ing in  length  until  mature  size  is  reached. 

Let  the  pupils  endeavor  to  collect  some  young  grasshop- 
pers representing  various  stages  of  growth,  and  place  these 
in  their  collections  beside  the  full-grown  one. 

By  searching  in  the  grass,  the  cast-off  skins  of  grasshop- 
pers may  be  occasionally  found  still  clinging  to  the  spears  of 
grass,  where  they  were  left  when  the  grasshoppers  shed  them. 


FIG.  88.— CAST-OFF  SKIN  OF  A  GRASSHOPPER.— The  grasshopper  has  shed  its  skin  while 
clinging  to  a  blade  of  grass.  The  skin  is  imperfect,  the  antennae  and  parts  of  its  legs  are 
broken ;  the  abdomen  is  shriveled,  and  does  not  show. 


HABITS   AND   STRUCTURE   OF  INSECTS.  91 

Fig.  88  shows  the  appearance  of  one  of  these  cast-off  skins. 

85.  Grasshoppers  are  often  infested  with  parasites.  Fre- 
quently the  grasshoppers,  in  a  sickly  condition,  are  met  with 
clinging  to  the  grass,  or  bushes.  A  careful  examination  of 
them  wrill  show  a  number  of  little  bright-red  mites  crawling 
on  them,  or  attached  near  the  base  of  the  wings,  and  evi- 
dently the  cause  of  their  weakness. 

Curious  cases  have  been  found  wherein  these  creatures 
had  met  with  fatal  accidents.  In  their  headlong  fall  to  the 


FIG.  89.— GRASSHOPPER  PIERCED  WITH  SPEAR  OF  GRASS. 

ground,  after  one  of  their  reckless  jumps,  they  are  liable  to 
have  their  armor  pierced  with  the  dried  spears  of  grass.  Fig. 
89  represents  a  grasshopper  which  had  been  pierced  in  this 


92  FIRST  BOOK   OF  ZOOLOGY. 

way,  the  dried  point  of  the  grass  probably  striking  the  head, 
and  then  glancing  off,  and  entering  between  the  head  and 
the  thorax. 

86.  In  studying  the  early  stages  of  the  mosquito,  it  was 
found  that  at  the  outset  the  animal  breathed  air  through  an 
opening  in  the  hinder  part  of  the  body ;  that  soon  after  this 
the  opening  closed,  and  air  was  taken  in  by  two  openings  on 
the  back,  but  in  no  case  did  the  insect  breathe  through  its 
mouth.  In  the  perfect  insect,  as  well  as  in  most  larvae,  there 
are  little  openings  along  the  sides  of  the  body.  These  little 
openings  communicate  with  tubes  which  branch,  and  sub- 
divide again  and  again,  sending  their  little  air-twigs  into 
every  part  of  the  body,  even  into  the  legs  and  the  veins  of 
the  wings.  These  little  tubes  represent  the  lungs  of  an  in- 
sect. They  necessarily  render  the  body  very  light  besides. 


FIG.  90.— INSECT  SHOWING  THE  SPIRACLES.— Grasshopper  with  the  wings  and  two  hinder  pairs 
of  legs  removed  to  show  spiracles,  or  openings  in  the  sides  of  the  body  which  commu- 
nicate with  the  air-tubes  within  the  body :  w,  showing  where  the  wings  were  attached ; 
h  and  m,  where  hind  and  middle  legs  were  attached ;  «,  spiracle  on  thorax ;  2,  tympanum. 

In  large  insects  like  the  grasshopper  the  minute  openings 
in  the  sides  of  the  body  can  be  plainly  seen  without  the  aid 
of  a  glass.  The  segments  of  the  abdomen  have  each  a  little 


HABITS  AND   STRUCTURE  OF  INSECTS.  93 

opening,  which  is  represented  in  the  figure  ;  and  where  the 
abdomen  joins  the  thorax,  a  cavity  lined  with  a  delicate  skin 
will  be  found,  which  is  called  the  tympanum,  and  is  supposed 
to  be  an  organ  of  hearing.  If  the  softer  parts  within  the 
body  of  an  insect  be  removed  and  slightly  compressed  be- 
tween two  pieces  of  thin  glass,  the  air-tubes,  looking  like  fine 
white  threads,  may  be  seen  with  an  ordinary  pocket-lens. 

The  air-tubes  are  called  trachece,  and  the  openings  on  the 
outside  of  the  body  which  communicate  with  them  are  called 
spiracles. 

87.  Insects  breathe  by  dilating  and  contracting  the  ab- 
dominal segments.    The  act  of  breathing  can  be  plainly  seen 
in  the  grasshopper  or  the  honey-bee,  and  it  will  be  noticed 
that  after  violent  exercise,  as  in  a  long  flight,  the  insect 
breathes  more  rapidly  than  when  it  has  been  at  rest  for  some 
time,  just  as  a  boy  after  running  finds  himself  compelled  to 
breathe  rapidly  for  a  while. 

After  violent  exercise  the  insect  gets  tired  and  rests.  Bees 
may  often  be  seen,  after  a  long  flight,  to  alight  in  the  grass 
near  a  flower,  and  for  a  while  appear  so  fatigued  that  they 
cannot  reach  the  flower,  but  remain  breathing  very  rapidly. 
Insects  have  curious  ways  of  resting  and  sleeping.  A  species 
of  wasp  has  been  observed  soundly  sleeping  while  holding  on 
to  a  blade  of  grass  by  its  jaws  alone,  the  fore-legs  just  touch- 
ing the  grass,  while  the  body  and  the  middle  and  hinder 
pair  of  legs  were  hanging  downward,  and  not  bearing  against 
the  grass  at  all,  as  shown  in  Fig.  91. 

88.  In  this  connection  it  may  be  well  to  allude  briefly  to 


94  FIRST  BOOK  OF  ZOOLOGY. 

the  manner  in  which  the  various  sounds  emitted  by  insects 
are  made.  It  is  obvious  that  the  vibration  of  the  wings  pro- 
duces the  loud  buzzing  sound  made  by  certain  insects.  But 
there  are  other  sounds  which  are  traced  directly  to  the 
effect  of  the  air  rushing  in  and  out  of  the  spiracles,  and 
impinging  on  certain  plates  whose  sharp  edges  border  the 
spiracle.  The  experiment  has  been  made  of  closing  the 


FIG.  91  .--WASP  SLEEPING  WHILE  HOLDING  ON  TO  A  BLADE  OF  GBASS  WITH  ITS  JAWS. 

spiracles  with  varnish,  when  all  noise  ceased.  It  is  believed 
that  the  mosquito  produces  its  remarkable  tones  in  this  way. 
Such  noises  have  always  been  associated  with  the  vibration 
of  the  wings,  because  the  noise  seems  to  be  made  when  the 
insect  is  flying,  but  the  cause  of  this  is  explained  by  sup- 
posing that  the  violent  muscular  action  of  moving  the  wings 
also  causes  the  air  to  be  violently  thrown  out  of  the  spiracles, 
and  as  a  proof  of  this  it  has  been  found  that  cutting  off  the 


HABITS  AND   STRUCTURE  OF  INSECTS.  95 

wings  of  such  an  insect,  while  modifying  the  sound,  by  no 
means  prevented  it  being  made  ;  and  it  is  a  fact  also  that  no 
sound  is  produced  by  other  insects  whose  wings  vibrate  with 
great  energy. 

89.  The  peculiar  chirp  of  the  cricket  is  made  by  the  fore- 
wings  being  rubbed  rapidly  against  the  hind-wings  upon 
which  they  rest;  one  of  the  large  veins  in  the  fore-wing 
being  thickened  and  notched  like  a  file,  and  the  wing  itself 
acting  as  a  resonant  body  in  augmenting  the  sound.  The 
males,  only,  make  this  sound ;  the  females  are  silent ;  and  if 
the  fore-wing  of  the  female  be  examined,  the  vein  in  ques- 
tion is  not  thickened,  nor  is  it  rough,  like  a  file. 

Mr.  Samuel  H.  Scudder  has  stated  that  the  grasshop- 
pers produce  their  sound,  or  stridulate,  in  four  different 
ways :  "  1.  By  rubbing  the  base  of  one  wing-cover  upon 
the  other,  using  for  that  purpose  the  veins  running  through 
the  middle  portion  of  the  wing ;  2.  By  a  similar  method,  but 
using  the  veins  of  the  inner  part  of  the  wing ;  3.  By  rub- 
bing the  inner  surface  of  the  hind-legs  against  the  outer  sur- 
face of  the  wing-covers;  and  4.  By  rubbing  together  the 
upper  surface  of  the  front  edge  of  the  wings  and  the  under 
surface  of  the  wing-covers.  The  insects  which  employ  the 
fourth  method  stridulate  during  flight — the  others  while  at 
rest.  To  the  first  group  belong  the  crickets ;  to  the  second, 
the  green  or  long-horned  grasshoppers  ;  to  the  third  and 
fourth,  certain  kinds  of  short-horned  or  jumping  grasshop- 


pers." 


90.  Harris,  in  describing  the  third  method  of  stridulation, 


96  FIRST  BOOK  OF  ZOOLOGY. 

says  that  "  their  instruments  may  rather  be  likened  to  vio- 
lins, their  hind-legs  being  the  bows,  and  the  projecting  edge 
of  the  wing-covers  the  strings,"  and  adds  that  when  a  grass- 
hopper begins  to  play  "  he  bends  the  shank  of  one  hind-leg 
beneath  the  thigh,  where  it  is  lodged  in  a  furrow  designed 
to  receive  it,  and  then  draws  the  leg  briskly  up  and  down 
several  times  against  the  projecting  lateral  edge  and  veins  of 
the  wing-cover.  He  does  not  play  both  fiddles  together,  but 
alternately,  for  a  little  time,  first  upon  one,  and  then  on  the 
other,  standing  meanwhile  upon  the  four  anterior  legs  and 
the  hind-leg  which  is  not  employed." 


FIG.  92.— Leg  of  a  Grasshopper  magnified,  showing  Ridge  of  Fine  Teeth  on  the  Inside  of  the 
Leg,  marked  a,  by  which  the  Insect  rasps  the  Wing ;  J,  c,  Different  Views  of  Eidge  of 
Fine  Teeth,  highly  magnified. 

A  figure  is  here  given  of  the  hind-leg  of  a  common  grass- 
hopper, showing  the  row  of  minute  teeth  which  occur  on  the 
inside  of  the  leg,  and  which  are  drawn  across  the  edge  of  the 
wing.  The  pupils  may  imitate  the  sound  thus  produced  by 
drawing  a  coarse  file,  or  the  teeth  of  a  comb,  rapidly  across 
the  edge  of  a  stiff  sheet  of  paper. 


HABITS  AND   STRUCTURE   OF   INSECTS.  97 


CHAPTEE 

HABITS   AND   STRUCTURE   OF   INSECTS    (CONTINUED). 

91.  A  LITTLE  bug,  called  the  tree-hopper,  has  a  peculiar 
history  in  its  young  state.     The  eggs  of  certain  species  are 
laid  in  the  ground,  and,  as  soon  as  these  hatch,  the  young 
ones  crawl  up  the  stems  of  grass,  and,  piercing  the  grass  with 
their  mouth-parts,  commence  to  suck  the  juices  contained 
therein.     While  this  action  is  going  on,  a  clear,  watery  fluid 
escapes  from  certain  pores  in  the  body,  and  in  a  short  time 
the  young  insect  is  completely  immersed  in  it.      As  it  is 
obliged  to  breathe  air,  it  secures  this  by  turning  up  the 
hinder  part  of  the  body,  and  by  means  of  little  appendages, 
clasping  a  bubble  of  air,  which  then  flows  along  the  under 
side  of  the  abdomen  ;  here  it  is  taken  in  through  the  spira- 
cles.    The  air  having  been  so  used,  is  allowed  to  escape  in 
the  fluid  in  which  the  insect  is  immersed.     This  operation 
is  repeated  over  and  over  again,  fresh  bubbles  of  air  being 
thus  secured,  and  then  escaping  in  the  fluid.     After  a  while 
the  fluid  becomes  filled  with  these  little  bubbles,  which  soon 
convert  it  into  a  frothy  substance,  and  this  is  the  origin  of 
the  white  flecks  which  occur  so  thickly  on  grass,  and  which 
is  here  commonly  called  frog-spit^  and,  in  England,  cuckoo- 
spittle. 

92.  There  are  certain  insects  belonging  to  the  same  group 
which  are  aquatic,  and  whose  young  come  to  the  surface  of 


98 


FIRST  BOOK  OF  ZOOLOGY. 


the  water,  and  in  the  same  manner  secure  air.  So  this  little 
tree-hopper,  while  in  the  young  state  sucking  the  juices  of 
grass,  and  completely  immersed  in  a  watery  fluid,  may  be 
looked  upon  as  an  aquatic  larva  during  this  stage. 


FIG.  93.— GRASS,  WITH  THE  FROTH 
UPON  IT,  a,  a,  and  a  Young  In- 
sect exposed  at  &. 


FIG.  94.— A  PORTION  OF  A  GRASS-STEM,  WITH  THE 
YOUNG  INSECTS  MAGNIFIED  :  a,  the  Insect  reach- 
ing out  the  Hinder  Part  of  the  Body  to  secure 
a  Bubble  of  Air;  &,  an  Insect  allowing  a  Bub- 
ble of  Air  to  escape  in  the  Fluid,  the  dotted  line 
&  indicates  the  bubble;  c,  the  Mouth- parts,  like 
a  Sting,  piercing  the  Grass. 


Let  the  pupils  collect  and  examine  this  froth,  and,  by 
carefully  wiping  it  away,  they  may  expose  the  young  insect 
fastened  to  the  grass. 

93.  The  insect  called  the  seventeen-year  cicada,  or  seven- 


HABITS  AND  STRUCTURE  OF  INSECTS.  99 

teen  year  locust  as  it  is  improperly  called,  has  an  interesting 
life-history. 

The  perfect  insect  is  shown  in  Fig.  95.  They  may  be 
known  by  the  peculiar  loud,  buzzing  sound  emitted  by  the 
male.  This  sound  can  oftentimes  be  heard  at  a  great  dis- 
tance. 


FIG.  95.— SEVENTEEN- YBAB  CICADA. 

The  seventeen-year  cicada  is  found  rarely  in  Southern 
New  England,  but  is  common  in  the  Southern  and  Western 
States.  This  species  exists  in  great  numbers,  and  does 
immense  damage  to  the  trees  which  it  infests.  The  female 
deposits  her  eggs  in  the  twigs  and  smaller  branches  of 
oaks.  Little  furrows  are  made  in  the  twig,  side  by  side,  and 
within  these  furrows  the  eggs  are  laid.  The  leaves  wither 
on  the  trees  from  the  injuries  inflicted  in  this  way.  Lit- 
tle insects  hatch  from  the  eggs,  entirely  different  in  appear- 
ance from  the  parent ;  and  these,  running  to  the  end  of  the 
twig,  fling  themselves  off,  and  falling  to  the  ground  dig 
their  way  down,  till  they  come  to  some  root  upon  which 
they  fasten,  and  with  a  piercing  sting  suck  the  juices  of 
the  root.  Here  they  remain  for  nearly  seventeen  years, 
slowly  growing.  At  the  end  of  that  time  they  assume  the 


100 


FIRST  BOOK  OF  ZOOLOGY. 


appearance  represented  in  Fig.  96.  At  the  proper  time  they 
crawl  out  of  the  ground,  and  their  skins  splitting  open  along 
the  back,  out  come  the  perfect  insects,  with  wings  and  all 
complete,  to  fly  away,  lay  their  eggs,  and  devastate  the 
forests. 

There  are  certain  species  which  do  not  occur  in  such 
numbers,  and  which  pass  through  all  their  changes  in  a  sin- 
gle year.  The  cast-off  skins  of  the  pupae  of  such  species  may 
be  often  found  clinging  to  apple-trees  and  fences  in  New 
England. 


FIG  96.— PUPA-CASE  OP  A  SPECIES  OF  NEW  ENGLAND  CICADA  OR  HARVEST-FLY,  CLINGINO 

TO  A  TWIG. 

The  pupils  should,  if  possible,  collect  a  twig  in  which 
the  eggs  have  been  deposited,  a  pupa-skin,  and  the  perfect 
insect. 


HABITS  AND  STRUCTURE  OF  INSECTS.  101 

CHAPTER    XIY. 

HABITS    AND    STRUCTURE   OF    INSECTS    (CONCLUDED). 

94.  THE  May-fly,  or  Ephemera,  is  one  of  the  most  com- 
mon insects  in  the  Western  States.  They  live  only  a  few 
weeks  in  their  perfect  state,  oftentimes  but  a  few  days. 
Their  eggs  are  laid  in  the  water,  and  the  larvae  live  in  the 
water  two  or  three  years.  At  the  end  of  this  time  they 
come  to  the  surface  in  immense  numbers,  and,  shedding 
their  skins,  come  out  as  winged  insects.  At  this  time  they 
resemble  their  perfect  state  eo  closely,  that  the  name  sub- 


FIG.  97.— LARVA  OF  EPHEMERA. 

(Reduced  from  Figure  by  J.  H.  Emerton,  in  Dr.  A.  8.  Packard's  Directions  for  collecting 
Insects,  Smithsonian  Institution.) 

imagos  is  given  to  them  in  this  condition.  They  often  fly 
a  considerable  distance  from  the  water,  alighting  on  the 
ground  and  trees.  Here  they  again  shed  their  skin,  and 
then  have  attained  their  perfect  state. 


102 


FIRST  BOOK   OF  ZOOLOGY. 


These  insects  occur  in  prodigious  numbers  in  certain 
parts  of  the  world.     In  some  regions  of  Europe  they  are  so 


FIG.  98.— EPUEMEBA. 


abundant  that  the  inhabitants  collect  them  in  heaps,  and  use 
them  as  dressing  for  the  land.     In  the  cities  bordering  the 


HABITS  AND  STRUCTURE  OF  INSECTS.  103 

great  lakes  it  is  a  common  sight  to  see  the  gas-posts  and 
adjoining  buildings  blackened  by  the  myriads  of  Ephemera 
which  have  been  blown  in  from  the  lakes  and  have  been  at- 
tracted by  the  lights.  The  following  figure  represents  a 
gas-post,  in  Cleveland,  Ohio,  as  it  appeared  with  Ephemera 
clinging  to  it : 


FIG.  99.— GAS-POST,  WITH  EPHEMEKA  CLINGING  TO  rr. 

95.  Another  group  of  insects  somewhat  resembling  the 
Ephemera  pass  their  larval  state  in  the  water. 

Some  of  their  larvae  are  called  caddis-worms,  or  case- 


104  FIRST  BOOK  OF  ZOOLOGY. 

worms,  and  are  inclosed  in  cases  of  cylindrical  and  other 
shapes.  These  are  variously  made  of  grains  of  sand,  bits 
of  bark  and  sticks,. and  other  fragments  of  convenient  size 
cemented  together.  Some  of  these  cases,  built  of  small 


FIG.  100.— CADDIS-WOBM,  WITH  ITS  CASE. 

grains  of  sand,  look  like  coiled  snail-shells.  Other  larvae 
shelter  themselves  in  bits  of  straw,  or  the  fragments  of 
hollow  stems  of  plants. 

Fig.  100  represents  the  larva  of  one  of  these  insects  in 
its  case,  which  is  made  of  bits  of  sticks  arranged  in  a  spiral 
course.  The  larva  drags  about  this  case,  and  as  it  grows  col- 
lects material  for  the  enlargement  of  its  tube. 

In  almost  any  quiet  pool  or  running  stream  these  curious 
cases  may  be  found,  containing  the  larvae  within. 


FIG.  101.— GALL-FLY. 


96.  The  curious  round  balls  called  gall-nuts,  which  are 
found  on  the  leaves  of  the  oak  and  of  other  trees,  are  pro- 
duced by  an  insect  called  the  gall-fly. 

The  eggs  are  deposited  in  the  substance  of  the  leaf,  and 


HABITS  AND   STRUCTURE   OF  INSECTS.  105 

it  may  be  that  the  larva,  by  its  presence  there,  causes  the 
unnatural  growth  of  the  leaf,  resulting  in  a  wart  or  tumor, 
and  sometimes  in  a  large  round  nut.  It  is  believed,  however, 
that  the  adult  insect,  in  depositing  the  egg,  also  stings  the 
leaf,  and,  poisoning  it  at  the  same  time,  induces  the  ab- 
normal growth  of  the  leaf.  Within  this  the  larva  feeds, 


FIG.  102.— GALL-NUT  ON  OAK-LEAF. 
(Copied  from  Harris's  "Insects  injurious  to  Vegetation,"  third  edition.) 

and  changes  into  the  pupa  state,  and  finally  into  the  perfect 
insect,  when  it  gnaws  its  way  out. 

In  the  autumn  the  pupils  will  find  the  gall-nuts  abun- 
dantly in  the  woods.  Let  them  collect  a  number  of  these, 
and,  on  carefully  cutting  them  open,  they  will  find  within  a 
tiny  oval  case,  ,and  upon  opening  this  they  will  discover 
snugly  stowed  away  a  little,  polished  black  fly  having  four 
wings.  The  creature  when  liberated  is  ready  to  fly  away. 


106 


FIRST  BOOK  OF  ZOOLOGY. 


Some  of  the  nuts  will  be  empty,  because  the  gall-insects 
have  already  escaped. 

Galls  are  also  produced  by  other  kinds  of  insects.  The 
following  figure,  which  represents  a  gall  common  on  the 
golden-rod,  is  produced  by  a  two-winged  fly.  The  figure 
represents  the  stem  or  stalk  unnaturally  swollen,  the  swollen 
portion  being  the  gall,  within  which  the  larva,  pupa,  or  per- 
fect insect,  may  be  found  if  the  creature  has  not  already 
escaped. 


FIG.  103.— GALL  ON  GOLDEN-KOD  STALK.-^P,  Pupa  removed  from  the  Gall. 

Let  the  pupils  arrange  in  their  collecting-box  a  leaf  with 
the  nut  attached,  a  nut  cut  open  showing  the  pupa-case,  and 
the  insect  pinned. 

97.  Only  a  few  brief  lessons  have  been  given  represent- 
ing the  life-history  of  a  butterfly,  mud-wasp,  mosquito,  spit- 


HABITS  AND   STRUCTURE   OF  INSECTS.  10? 

tie-insect,  seventeen-year  cicada,  May-fly,  and  gall-fly.  Let 
the  pupils  endeavor  from  their  own  observations  to  make 
additional  life  -  histories,  or  record  facts,  concerning  other 
insects,  such  as  the  honey-bee,  paper-wasp,  and  a  great  many 
other  common  insects,  of  which  no  mention  has  been  made 
here.  The  turning  over  of  stones  and  logs  in  the  woods 
wTill  oftentimes  expose  the  burrows  of  ants,  and  the  ants 
will  probably  be  found  busily  engaged  in  carrying  off  long, 
white,  oval  cases,  which  look  like  eggs ;  let  the  pupils  collect 
some  of  these,  and  see  if  they  can  find  out  what  stage  in  the 
"history  of  the  insect  they  represent. 

98.  An  instinct  which  appears  wonderful  to  us,  prompts 
the  insect  to  seek  appropriate  places  for  the  deposition  of 
her   eggs.      The   butterfly,   for    example,    seeks    for   food 
the    nectar    of    flowers;    its    larvae,   however,   must    have 
leaves  upon  which  to  feed,  and  the  instinct  of  the  butterfly 
impels  it  to  deposit  its  eggs  in  a  place  where  the  young 
shall   find   their  appropriate   food.      It  has  been  learned 
also   that   other  insects   store    up    animal    food   for  their 
young,  as  in  the  case  of  the  mud-wasp,  where  spiders  are 
imprisoned  in  cells  in  which  the  eggs  have  been  previously 
laid. 

The  gall-flies  deposit  their  eggs  directly  in  the  substance 
of  the  leaf. 

99.  Another  group  of  insects,  much  resembling  the  gall- 
flies, deposit  their  eggs  directly  in  the  bodies  of  the  larvae 
and  pupse  of   other  insects.      They  are  called  ichneumon- 
flies.     These  insects  have  on  the  hinder  part  of  the  body  a 


108  FIRST  BOOK   OF  ZOOLOGY. 

sharp,  piercing  sting,  and  with  this  organ  the  necessary  hole 
is  made  through  which  the  egg  is  deposited. 

A  caterpillar  soon  hatches  from  the  egg  thus  deposited 
by  the  ichneumon-fly,  and  feeds  upon  the  fatty  portions  of 
the  body  of  the  larva  in  which  it  has  been  so  placed.  But 
this  larva  containing  the  ichneumon-caterpillar,  meanwhile, 
completes  its  growth  and  changes  into  a  chrysalis,  when  the 
inclosed  ichneumon-larva  devours  the  entire  contents  of  the 
chrysalis,  and  then  changing  into  the  pupa  state  soon  emerges 
as  an  ichneumon-fly,  to  go  in  quest  of  caterpillars,  in  which 
to  deposit  its  eggs.  Thus  it  will  often  happen  that  a  num- 
ber of  cocoons  have  been  collected,  from  which  ought  to 
appear  a  certain  kind  of  moth,  for  example,  but  from  many 
of  them  a  brown  ichneumon-fly  will  emerge,  a  sight  quite 
as  startling,  to  one  not  familiar  with  insects,  as  if  a  robin 
should  be  seen  to  hatch  from  a  hen's-egg. 

If  the  pupils  will  collect  from  the  fences  a  large  number 
of  the  chrysalides  of  the  common  yellow  cabbage-butterfly, 
and  keep  them  in  a  box,  with  a  piece  of  glass  for  a  cover, 
they  will  observe  that  while  butterflies  come  from  many, 
from  others,  which  have  already  changed  to  a  lighter  color, 
little  black  flies  will  appear,  crawling  out  of  holes  in  the  side 
of  the  chrysalis  which  have  been  made  by  some  of  the  im- 
prisoned ichneumons.  (See  Fig.  104.) 

100.  Nearly  every  species  of  insect  is  infested  by  one  or 
more  species  of  ichneumons,  which  deposit  their  eggs  within 
the  pupse,  or  the  larvse,  or  even  in  the  eggs  themselves. 

There  are  some  species  of  ichneumons  which  deposit  their 


SPIDERS.  109 

eggs  within  the  eggs  of  the  canker-worm  moth,  and,  as  tiny 
as  these  eggs  are,  they  are  still  large  enough  to  furnish  nour- 
ishment and  room  for  the  complete  development  of  the 
insect  feeding  within. 

In  Fig.  74  an  ichneumon-fly  is  shown  on  the  wing,  in 
search  of  caterpillars  wherein  to  deposit  her  eggs. 

Fig.  67  also  represents  an  ichneumon-fly  of  large  size. 

Fig.  104  represents  ichneumon-flies  escaping  from  the 
chrysalis  of  the  cabbage-worm  butterfly. 


FIG.  104.— CHBYSALIS  OF  THE  CABBAGE- WORM,  FROM  WHICH  ABE  SEEN  ESCAPING  ICH- 
NEUMON-FLIES. 


CHAPTER   XY. 

SPIDERS. 

101.  FOR  this  lesson  the  pupils  are  to  collect  a  number 
of  spiders,  securing,  if  possible,  the  largest  specimens.  A 
wide-mouthed  bottle,  with  a  little  alcohol,  will  answer  to 
collect  them  in.  Let  each  pupil  select  the  largest  specimen 
to  study,  and  pin  it  to  a  piece  of  cork,  or  to  a  soft  pine  strip. 
The  legs  are  to  be  arranged  with  two  pairs  pointing  forward 
and  two  pairs  pointing  backward,  as  shown  in  Fig.  105. 

Let  them  study  the  following  characters  with  the  speci- 
men before  them : 

The  spider  is  divided  into  two  regions.  That  region  or 
part  to  which  the  legs  are  attached  is  called  the  cephalo- 


110 


FIRST  BOOK   OF  ZOOLOGY. 


thorax.  The  hinder  region  is  called  the  abdomen.  Instead 
of  having  a  separate  head,  as  in  true  insects,  the  spider  has 
its  head  and  thorax  combined,  and  hence  this  part  is  called 
the  cephalo-thorax,  a  compound  word  meaning  head-thorax. 


A  E     8 

FIG.  105.— COMMON  GARDEN  SPIDER.— A,  as  seen  from  above;  J5,  as  seen  from  below;  p> 
Palpi ;  «i,  Mandibles ;  8,  Spinnerets  from  which  the  Spider's  Thread  issues. 

102.  The  spider  has  four  pairs  of  legs,  instead  of  three 
pairs  of  legs  as  in  the  true  insects.  Projecting  in  front  are 
a  pair  of  jointed  feelers  called  palpi  (see  Fig.  105,  p). 
These  look  very  much  like  legs,  and  in  very  young  spiders 
can  scarcely  be  distinguished  from  them. 


12pm  8   s         4 

FIG.  106. — SIDE- VIEW  OF  COMMON  GAEDEN  SPIDEB. — £?,  Cephalo-thorax;  A,  Abdomen;  1,2, 
8, 4,  First,  Second,  Third,  and  Fourth  Pairs  of  Legs ;  «,  Spinnerets ;  w,  Mandibles ;  p,  Palpi. 


SPIDERS. 


Ill 


The  mouth  is  armed  with  a  pair  of  jaws  which  are  at- 
tached above  the  mouth  and  hang  down  in  front,  at  the 
end  of  which  are  the  poison-fangs.  With  these  they  are 
enabled  to  secure  and  kill  the  flies  and  other  insects  upon 
which  they  feed.  The  following  figure  represents  the  jaws 
or  mandibles. 


p  I  m 

Fis.  107.— FEONT  PORTION  OP  COMMON  GARDEN  SPIDEK  GREATLY  ENLARGED,  showing,  pp, 
Palpi ;  w,  Mandibles ;  II,  &  Portion  of  the  First  Pair  of  Legs,  and  above,  the  Front  of  the 
Cephalo-thorax,  with  the  Eight  Eyes  upon  it. 

Directly  behind  the  mandibles,  are  two  smaller  jaws, 
called  maxillse  (see  Fig.  108),  which  aid  in  crushing  the  food 
and  arranging  it  for  the  mouth. 


FIG.  10S. — INNER  JAWS,  OR  MAXILLA,  OF  A  COMMON  GARDEN  SPIDER. — The  first  Joints  of 
the  Palpi  are  seen  also. 

The  spider  has  eight  eyes,  situated  on  the  front  part  of 
the  cephalo-thorax.    They  look  like  little  black  beads,  and  in 


112 


FIRST  BOOK  OF  ZOOLOGY. 


large  spiders  can  be  easily  seen  withciut  the  aid  of  a  magni- 
fying-glass. 

103.  The  abdomen  has  little  appendages  at  its  hinder  end 
called  spinnerets,  and  from  these  the  spider  produces  the 
thread  with  which  it  builds  its  nests  and  nets,  the  nets  being 
commonly  called  spiders'  "webs. 

Highly  magnified  the  spinnerets  appear  as  blunt  protu- 
berances arranged  together  in  pairs,  and  capable  of  being 
contracted  or  expanded.  These  spinnerets  are  covered 
with  hundreds  of  jointed  hairs  which  are  perforated  and 
through  which  the  web-forming  material  escapes.  This  ma- 
terial is  fluid  and  something  like  the  white  of  an  egg. 
Escaping  from  the  body,  through  hundreds  of  these  minute 
openings,  the  strands  of  this  fluid  diy  almost  instantly,  and, 
uniting,  form  the  delicate,  yet  comparatively  strong,  thread  of 
the  spider.  Thus  it  will  be  seen  that  the  thread  of  the 
spider  is  composed  of  hundreds  of  strands,  which  may  be 
often  separated  just  as  the  fibres  of  a  rope  may  be  pulled 
apart.  Under  the  microscope  the  posterior  end  of  the  abdo- 
men with  the  spinnerets  looks  like  this. 


FIG.  109. — SFINNEKETS  OF  A  SPIDER. — £,  one  of  the  Tubular  Hairs  from  the  Spinneret8,  highly 

magnified. 


SPIDERS.  113 

104.  As  the  thread  issues  from  the  spinnerets,  the  spider 
guides  it  with  its  hind  pair  of  feet,  and  these  are  curiously 
adapted  for  the  purpose  not  only  of  holding  and  guiding  the 
thread,  but  also  of  enabling  the  spider  to  run  rapidly  across 
its  nets  without  getting  entangled,  while  other  animals  be- 
come helplessly  ensnared  in  attempting  the  same  thing. 

The  ends  of  the  legs  terminate  in  three  claws,  a  pair  of 
larger  ones  generally  notched  like  a  comb,  and  a  third  one 
like  a  spine  which  acts  as  a  thumb.  Other  notched  spines 
or  hairs  also  aid  in  securing  a  hold  upon  the  web,  and  even 
if  these  fail  to  secure  a  footing,  the  leg  itself  is  covered  with 
long  stiff  bristles  pointing  downward  which  are  sure  to  catch 
in  the  web.  The  two  large  notched  claws,  as  well  as  the 
other  claw  and  spines,  are  highly  polished,  and  consequently 
present  no  roughened  surface  to  which  the  thread  will 
adhere. 

The  following  figure  (Fig.  110)  represents  the  end  of  a 
spider's  leg  magnified,  showing  the  arrangement  of  hooks 
and  claws. 


t    m      o 

FIG.  110.— END  OF  A  COMMON  GARDEN  SPIDER'S  LEG  MAGNIFIED.— o,  Outer  Claws;  »t, 
Middle  Claw;  t,  Toothed  Hairs. 

105.  By  observing  the   spiders  which  build  their  nets 
across  the  openings  of  windows  and  in   other  convenient 


114  FIRST  BOOK  OF  ZOOLOGY. 

places,  and  while  at  work,  they  may  be  seen  to  use  their 
hind-feet  in  apparently  drawing  out  the  thread  as  it  were 
from  the  spinnerets.  It  will  be  observed  that  the  thread 
issues  in  a  broad  band,  and,  when  these  spiders  are  sluggish, 
their  thread  may  be  caught  on  the  end  of  a  pencil  by  gently 
rubbing  the  spinnerets  with  it,  and  then  by  withdrawing  the 
pencil  the  thread  may  be  reeled  off. 

The  various  kinds  of  nets  are  adapted  to  entrap  the 
spider's  food,  which  consists  of  flies  and  other  insects. 

Certain  kinds  of  spiders  do  not  build  nets,  but  go  in 
search  of  their  prey  by  stealthily  creeping  up  and  pouncing 
upon  it  unawares. 

It  is  a  very  interesting  sight  to  watch  the  little  black-and- 
white  spider  (so  common  on  the  sides  of  houses)  slyly  approach 
a  fly  which  has  alighted  near  it.  If  the  spider  is  on  the  side 
of  a  window-sill  and  a  fly  has  alighted  near  it,  the  spider 
instantly  turns  round,  facing  the  fly,  cautiously  and  very 
slowly  moves  backward,  till  it  gets  on  the  upper  side  of  the 
window-sill  and  out  of  sight,  when  it  rapidly  approaches,  now 
and  then  peering  over  the  edge  of  the  sill,  to  see  where  the 
fly  is,  and,  finally  getting  directly  above  the  fly,  it  gathers  its 
legs  for  a  jump,  securing  its  thread  to  the  window-sill  at  the 
same  time,  and  then  with  a  sudden  spring  seizes  the  fly  in  its 
jaws.  Sometimes  the  insect  is  much  larger  than  the  spider, 
and  flies  away,  with  the  spider  tightly  clinging  to  it ;  the 
thread,  however,  holds  fast,  though  sometimes  run  out  to  the 
length  of  a  foot  or  more.  Soon  the  poison  of  the  spider  takes 
effect,  and  the  fly  gradually  weakens,  and  ceases  its  strug- 


SPIDERS.  115 

gles,  when  the  spider  carries  it  off  to  some  nook,  there  to  de- 
vour it. 

106.  One  of  the  most  common  spider-nets  is  like  the  one 
shown  in  Fig.  74.  If  the  place  selected  is  in  the  opening 
of  a  window  or  similar  place,  the  spider  first  runs  a  few 
threads  as  a  sort  of  framework,  to  which  are  to  be  afterward 
attached  the  radiating  threads,  that  is,  those  which  run  from 
the  centre  of  the  net  to  the  sides.  Having  arranged  these 
so  near  together  that  the  spider  can  easily  reach  from  one 
radiating  thread  to  the  other,  the  creature  commences  at  the 
centre  of  the  net,  and  runs  a  thread  from  one  radiating  thread 
to  the  other  in  a  rapidly-unwinding  spiral  till  it  reaches  the 
outer  edge  of  the  net.  This  is  to  form  a  staging,  and  also 
the  better  to  hold  the  radiating  threads  in  place.  It  then 
commences  at  the  outside,  and  going  back  over  its  last  course 
carefully  constructs  the  permanent  mesh ;  and,  as  it  comes  to 
each  radiating  thread,  it  will  be  seen  to  attach  to  it  the 
thread  it  is  now  making,  by  simply  pressing  the  spinnerets 
against  it.  As  it  goes  around  again  and  again,  continually 
lessening  the  circle,  it  gathers  up  the  thread  which  was  first 
laid  as  a  staging,  and,  rolling  it  up  in  little  balls,  drops 
it  to  the  ground.  This  habit  has  led  to  the  impression 
that  the  spider  eats  its  web.  The  circular  threads  are 
glutinous,  while  the  radiating  threads  are  smooth,  and  this 
can  be  proved  by  throwing  dust  through  the  net,  when  the 
cross-threads  will  catch  and  hold  the  dust,  while  the  radiat- 
ing threads  will  remain  clean.  The  actual  centre  of  the  net 
is  not  the  geometrical  or  true  centre,  but  a  little  above  it. 


116  FIRST  BOOK  OF  ZOOLOGY. 

It  may  be  observed,  too,  that  the  net  does  not  stand  vertical, 
but  leans  a  little,  and  the  spider  having  completed  the  net 
takes  a  position  in  the  actual  centre  of  the  net,  head  down- 
ward and  on  the  inclining  side  of  the  net.  With  its  legs 
outstretched,  and  resting  on  the  radiating  lines,  it  can  feel  the 
slightest  jar  or  agitation  made  by  a  struggling  insect.  The 
spider  being  above  the  true  centre  of  the  net  and  on  the  in- 
clining side,  if  the  fly  has  become  entangled  below  the  centre, 
it  can  instantly  drop  to  the  desired  point  suspended  by  the 
ever-ready  thread  which  it  makes,  and,  swinging  to  the  net, 
it  almost  instantly  catches  the  fly. 

The  pupils  would  do  well  to  watch  the  spiders  while  they 
are  constructing  their  nets,  and  to  observe  and  describe,  or 
sketch  in  outline,  the  different  kinds  of  nets  they  find  and 
the  kinds  of  spiders  which  construct  them. 

107.  Besides  the  nets  made  by  spiders  to  ensnare  insects, 
some  species  have  the  power  of  running  out  a  long  thread 
which  answers  the  purpose  of  a  balloon  in  raising  them  from 
the  ground  and  carrying  them  floating  a  long  distance  in  the 
air.  In  constructing  this  buoyant  means  of  transportation, 
the  spider  does  it  at  peculiar  times  of  the  day,  and  in  peculiar 
positions.  Selecting  some  place  where  the  heated  air  is  rising 
from  the  ground  or  from  the  side  of  a  fence,  it  turns  up 
its  abdomen  and  allows  the  rising  current  of  air  to  carry 
upward  the  thread  which  is  being  made,  and,  when  this  thread 
is  of  sufficient  length  for  its  buoyancy  to  overcome  the  weight 
of  the  spider,  it  floats  away  with  the  spider  hanging  below. 

The  following  represents  the  young  spider  in  the  attij 


SPIDERS. 


tude  of  throwing  out  its  thread  for  the  purpose  of  sailing 
in  the  air. 

Yoyagers  often  meet  with  these  spiders  in  myriads  as 
the  wind  sweeps  them  from  the  land. 


PIG.  111.— YotTNG  SPIDER  GREATLY  ENLARGED,  SHOWING  ITS  ArrmrDE  IN  THROWING  OTTT  THE 
THREAD,  PREVIOUS  TO  RISING  FROM  THE  GROUND.    (Copied  from  a  Figure  by  J.  H.  Emerton . ) 

108.  The  spider  also  constructs  cases  to  hold  her  eggs,  and 
lines  them  warmly  with  the  finest  web.  These  nests  vary 
greatly  in  appearance.  A  very  common  variety,  somewhat 
oval  in  shape,  may  be  found  suspended  in  barns  and  sheds. 
The  pupils  should  collect  and  open  these  cases  or  nests,  and 
they  will  be  found  to  contain  little  eggs,  sometimes  rolling 
out  like  beads  into  the  hand,  or,  the  eggs  having  hatched, 
hundreds  of  little  spiders  will  appear  moving  within  the  nest. 

Nests,  or,  more  properly  speaking,  egg-cases  of  different 
kinds,  may  be  collected  under  stones  and  logs,  and  wherever 
spiders'  nests  occur.  The  little  spiders  hatching  from  the  egg 


118 


FIRST   BOOK   OF  ZOOLOGY. 


will  grow  to  twice  their  size  in  the  nest,  without  apparent 
food,  and  it  becomes  evident  that,  in  some  cases,  they 
must  eat  each  other,  as  Prof.  Wilder  has  observed  within 
some  of  the  egg-cases  a  far  less  number  of  spiders  than  there 
were  eggs  in  the  nest  at  the  outset.  These  nests  may  be 
kept  in  boxes,  and  the  eggs  will  hatch  in  due  time. 


AEG 

FIG.  112.— SPIDERS'  NESTS  OF  DIFFERENT  KINDS  CONTAINING  EGGS.— A  and  C  are  common 
nests  in  sheds  and  barns;  B  was  found  under  a.  board  in  the  field,  the  part  containing  the 
eggs  stands  upon  a  stalk. 

109.  The  young  spider  comes  from  the  egg  resembling  in 
form  the  parent  spider,  except  that  the  legs  are  much  shorter 
in  proportion  to  his  relative  size,  and  the  palpi  appear  so 
large  that  they  look  like  another  pair  of  legs,  as  they  then 
are  in  fact,  but  they  afterward  become  modified  to  feelers. 


FIG.  113.— ENLARGED  FIGURE  OF  A  YOUNG  SPIDER  JUST  FROM  THE  EGG,  WITH  THE  FIRST 
MOULT,  m,  adhering  to  the  Hinder  Part  of  the  Body ;  y,  the  Natural  Size  of  the  Spider ;  I, 
extremity  of  a  Leg  highly  magnified,  showing  an  Outer  Skin  which  has  not  been  shed. 


SPIDERS.  119 

As  the  young  spider  grows,  it  sheds  its  skin  at  short  inter- 
vals of  time.  If  the  pupils  will  examine  the  young  spider 
soon  after  it  is  hatched  from  the  egg,  they  will  find  attached 
to  the  hinder  part  of  the  body  the  skin  which  has  just  been 
shed.  This  curious  process  of  shedding  the  skin,  or  moulting, 
occurs  at  intervals,  till  the  spider  has  reached  adult  size. 


FIG.  114.— THE  CAST-OFF  SKIN  OF  AN  ADULT  SPIDEE. 

110.  The  cast-off  skins  of  spiders  are  very  common  in 
their  webs,  and,  if  the  pupils  examine  any  barn-window 
which  is  covered  with  spider's  webs,  they  will  be  sure  to  find 
some  of  these  cast-off  skins,  like  the  one  represented  in  Fig. 
114. 

The  mother-spider,  generally  so  timid,  overcomes  her  fear 
during  the  time  she  has  the  care  of  her  eggs,  and  with 
many  spiders  the  egg-cases  are  directly  cared  for  by  the 
mother,  she  oftentimes  carrying  them  about  with  her  or  hold- 
ing on  to  them  and  showing  the  greatest  solicitude  for  their 
safety.  Let  the  pupils  try  to  separate  the  egg-case  from  the 
mother-spider,  and  they  will  then  learn  how  courageous  the 
spider  is  at  this  time,  and  how  persistently  she  remains  by 
her  eggs.  Some  species  of  spiders  carry  their  young  on 
their  backs,  and  move  about  with  them. 


120  FIRST  BOOK  OF  ZOOLOGY. 

A  small  black  spider  was  picked  up  in  the  woods,  which 
had  her  body  entirely  covered  with  young  spiders,  which 
were  evidently  newly  hatched.  When  the  mother-spider 
was  picked  up,  all  the  little  spiders  becoming  frightened 
jumped  off,  but  just  before  jumping  each  one  attached  a  tiny 
thread  to  its  mother's  back,  and  as  the  spider  was  held  up  in 
the  air  there  hung  below,  suspended  by  invisible  threads, 
the  whole  progeny  looking  like  little  black  beads.  The 
mother-spider  was  then  thrown  down  among  the  dead  leaves, 
sticks,  and  pine-cones.  She  did  not  run  away,  however,  but 
waited  till  all  of  the  young  ones  had  found  their  way  through 
this  tangled  wilderness,  safely  back  to  their  mother,  and  this 
they  accomplished  by  means  of  their  threads,  one  end  of  which 
they  had  previously  attached  to  her  back.  Having  waited 
till  all  had  been  gathered  in  this  way,  she  continued  her 
journey. 

111.  The  spider  has  no  power  of  throwing  or  ejecting 
its  thread  to  distant  objects,  as  many  suppose.  "When  threads 
are  seen  stretching  from  one  tree  to  another,  the  spider  has 
caused  the  thread  to  issue  from  the  spinnerets,  and  the  wind 
has  then  caught  it  and  borne  it  along,  till  finally  it  gets 
entangled  with  some  object,  and  in  this  way  the  spider  is 
enabled  to  cross  from  one  point  to  another. 

These  creatures  are  not  so  dangerous  as  many  suppose,  and 
but  very  few  authenticated  cases  are  known  of  man  having 
been  bitten  by  these   animals;   though   the  larger  spiders 
at  the  South,  and  in  California,  as  the  tarantula,  for  exam 
pie,  can  inflict  a  dangerous  wound. 


DADDY-LONG-LEGS,  CENTIPEDES,  AND   MILLIPEDES.       121 

CHAPTER  XYI. 

DADDY-LONG-LEGS,    CENTIPEDES,    AND   MILLEPEDES. 

112.  IN  the  insects  proper,  or  true  insects,  the  pupil  has 
learned  that  the  head,  thorax,  and  abdomen,  are  separated 
into  three  regions  or  parts.     In  the  spiders,  it  has  been  seen 
that  the  head  and  thorax  are   combined,  forming  a  single 
region  or  part,  and  called  the  cephalo-thorax,  while  the  ab- 
domen appears  as  a  distinct  part.     There  is  another  group 
of  animals  allied  to  the  spiders,  the  individuals  thereof  hav- 
ing four  pairs  of  legs,  and  the  head,  thorax,  and  abdomen, 
more  or  less  merged  together.     The  animals  belonging  to 
this  group  are  called  in  various  parts  of  the  country,  daddy- 
long-legs^  granddaddy-long-legs,  grandfather-grayleards,  and 
harvest-men,  and  in  northern  New  York  are  known  by  the 
name  of  "  grab  for  gray  bears." 

Certain  species  are  common  around  houses  and  sheds, 
others  are  found  in  the  woods.  They  are  easily  recognized 
by  their  small  bodies  and  extremely  long  and  slender  legs. 
It  is  difficult  to  hold  them  in  the  fingers,  as  some  of  the  legs 
are  liable  to  drop  off  on  the  slightest  effort  made  to  retain 
the  animals. 

In  the  middle  and  on  the  back  of  the  cephalo-thorax,  there 
is  a  slight  eminence,  upon  which  are  situated  the  eyes,  two  in 
number.  The  abdomen  appears  distinctly  segmented. 

113.  Their  food  consists  of  small  insects,  such  as  flies  and 


12! 


FIRST  BOOK  OF  ZOOLOGY. 


mosquitoes ;  and  these  they  go  in  quest  of,  slyly  approaching 
and  pouncing  on  their  victim  and  seizing  it  with  their  mandi- 
bles, which  are  furnished  at  their  ends  with  a  pair  of  nippers, 
which  enable  them  to  retain  their  prey.  (See  Fig.  115,  m.) 

They  build  no  net  to  entrap  their  prey,  and  are  weak  and 
helpless  compared  with  their  higher  relatives,  the  true  spiders. 
They  are  dependent  then  for  food  upon  such  insects  as  they 
can  overcome,  and  these  they  devour,  differing  in  this  respect 
from  the  rapacious  spiders  which  suck  the  fluid  contents  of 
their  prey,  rejecting  the  rest.  Certain  species  are  known  to 


FIG.  115.— YOTTNG  DADDY-LONG-LEGS,  ENLARGED  :  y,  showing  Natural  Size ;  J?,  Under  Side 
of  Body  still  more  enlarged ;  m,  Mandible  of  Left  Side ;  p,  Palpus  of  Eight  Side ;  P, 
Palpus,  greatly  enlarged;  P  C,  End  of  Palpus,  showing  Notched  Claw;  Z,  End  of  Leg, 
showing  Claw;  E,  Eye-Prominence,  with  the  Two  Eyes.  (The  three  last-mentioned  Fig- 
ures are  greatly  magnified.) 


DADDY-LONG-LEGS,  CENTIPEDES,  AND  MILLIPEDES.       123 

be  cannibals,  as  some  have  been  seen  to  pounce  upon  a  brother 
daddy-long-legs  and  devour  it,  leaving  only  the  legs. 

It  is  believed  that  in  the  Northern  States  they  do  not  sur- 
vive the  winter,  as  in  the  spring  only  young  ones  are  seen, 
and  these  attain  full  size  by  autumn.  At  this  season,  the  eggs 
are  laid  under  stones  and  in  the  cracks  of  boards  and  other 
protected  places,  where  they  remain  to  hatch  out  in  the  fol- 
lowing spring. 

114.  Under  old  boards  in  gardens  and  hidden  beneath 
stones  and  dead  leaves  in  the  fields  and  woods,  the  pupils 
will  find  the  other  creatures  to  be  studied  in  this  lesson. 
They  are  commonly  known  as  centipedes,  and  in  the  Eastern 
States,  at  least,  are  also  known  as  earwigs ;  though  the  ear- 
wig in  England  is  an  entirely  different  animal,  being  a  true 
six-legged  insect. 

The  centipede  belongs  to  a  group  of  animals  called  Myri- 
apods,  and  the  animals  belonging  to  this  group  are  composed 
of.  a  great  many  similar  segments,  some  species  having  as 
few  as  ten  segments,  others  having  over  two  hundred  seg- 
ments. In  this  latter  respect,  these  creatures  resemble  the 
worms,  but  differ  from  the  worms  in  having  jointed  legs  and 
antennae,  in  these  last-named  characters  resembling  the  in- 
sects, besides  having  other  affinities  with  them,  in  breathing 
air  through  spiracles  and  tracheae  which  run  through  the 
body. 

There  are  two  very  distinct  groups  of  Myriapods ;  one 
group  comprising  the  true  centipedes,  in  which  the  body  is 
flattened,  the  segments  loosely  joined,  and  the  legs  gener- 


124 


FIRST   BOOK   OF  ZOOLOGY. 


ally  equaling,  and  sometimes  exceeding,  the  width  of  the 
body. 

The  segments  in  many  cases  are  unequal  in  length,  some 
of  them  being  very  short  and  alternating  with  long  ones, 
though  all  bear  a  pair  of  legs  below.  The  antennae  are  much 
longer  than  the  legs,  and  are  often  composed  of  a  great  many 
joints.  A  pair  of  modified  legs  reach  out  behind  and  look 
like  a  hinder  pair  of  antennae. 

In  a  few  forms  the  eyes  are  compound  as  in  the  insects, 
while  in  others  the  eyes  are  separate  as  in  the  spider,  and 
are  called  ocelli.  These  are  grouped  on  each  side  of  the  head, 
at  the  base  of  the  antennae. 


A  magnified  view  of  the  head,  showing  group  of 
FIG.  116. — COMMON  CENTIPEDE,  eyes  at  the  base  of  antennae.    A  few  joints  only  of 

NATUBAL  SIZE.  the  antennae  are  shown. 


115.  The  jaws  or  mandibles  are  large  and  jointed,  with 
the  terminal  joint  long  and  sharp  as  in  the  spiders.  The 
other  pairs  of  jointed  appendages  act  also  as  mouth-parts. 
The  under  lip  is  notched  with  fine  teeth,  as  shown  in  the  fol- 
lowing figure,  which  represents  the  under  surface  of  the  head 
of  the  species  of  centipede  shown  in  Fig.  116. 


DADDY-LONG-LEGS,  CENTIPEDES,  AND  MILLIPEDES.       125 

These  creatures  are  active  in  their  motions,  and  rapacious 
in  their  habits.  Some  of  them  feed  on  small  insects,  others 
attack  earthworms.  Their  bite  is  venomous  to  insects,  and 
one  species  having  very  long  legs  will  produce  by  its  bite  a 
severe  pain  lasting  several  hours.  A  large  species  found  in 
the  Southern  States,  and  in  the  tropics,  and  commonly  known 


FIG.  117.— SHOWING  MAGNIFIED  VIEW  OF  THE  UNDER  SUBFACE  OF  THE  HEAD  OF  A  CENTI- 
PEDE: a,  Antenna;  m  p,  Maxillary  Palpus;  /.;',  Foot-jaw;  /,  Poison-Fang  of  Foot-jaw; 
I,  Labium;  m,  Maxilla.  The  Mandibles  are  hidden  behind  the  other  parts,  and  do  not 
show. 

as  the  centipede,  is  considered  a  dangerous  animal  from  its 
bite.  The  feet  of  this  species  are  supposed  to  poison  by  their 
touch,  since,  when  they  run  over  the  flesh,  small  ulcers  appear 
where  the  feet  have  come  in  contact  with  the  skin.  The 
pupils  may  collect  these  animals,  and  either  dry  them  and 
stick  them  to  cards,  or  preserve  the  specimens  in  vials  filled 
with  alcohol. 

116.  The  other  group  of  myriapods,  commonly  known  as 


126 


FIRST  BOOK  OF  ZOOLOGY. 


millepedes,  have  a  long,  cylindrical,  and  oftentimes  shiny  body, 
composed  of  a  great  many  segments  so  smoothly  joined  to- 
gether that  it  is  difficult  to  see  the  separation  between  them. 
The  antennae  are  short,  there  are  no  long  caudal  append- 
ages, and  the  legs  are  short  and  feeble.  At  first  sight  it 
would  appear  that  these  creatures  were  exceptional  among 
insects  and  spiders,  in  having  two  pairs  of  legs  to  one  seg- 
ment ;  but  it  has  been  learned,  by  studying  the  very  young 
millepede,  that  there  is  really  but  one  pair  of  legs  to  a  seg- 
ment, but  that  the  segments  grow  together  in  pairs,  so  that 
each  apparent  segment  is  really  two  segments  united. 


compound  eye. 


antenna. 


A  E 

FIG.  118.— A  COMMON.  MILLIPEDE.  The  line  underneath  the  figure  represents  the  length  of 
the  specimen  from  which  the  drawing  was  made.  A,  &  Magnified  View  of  the  Head  of  the 
Milliped  represented  above ;  £,  a  Magnified  View  of  the  Left  Jaw. 

These  creatures  live  on  decaying  matter,  and  are  slow  and 
weak  in  all  their  movements.  When  touched,  or  alarmed, 
they  coil  up  in  a  closely-wound  roll.  The  body  is  hard,  and 
the  animal  can  be  stuck  on  a  card  for  the  cabinet.  The  eggs, 
to  the  number  of  sixty  or  more,  are  laid  in  little  burrows 


DADDY-LONG-LEGS,  CENTIPEDES,  AND  MILLIPEDES.       127 

previously  prepared  by  the  creature  in  earth  that  is  neither 
too  moist  nor  yet  too  dry.  In  preparing  the  burrow  the 
female  makes  use  of  the  fluid  which  comes  from  her  mouth, 
and  which  enables  her  to  stick  the  earth  together  in  little 
balls,  and  these  she  passes  up  from  her  burrow  by  means  of 
the  little  legs  which  grasp  the  pellet  and  convey  it  from  one 
pair  of  legs  to  the  next  pair,  and  so  on  till  it  is  thrown 
out  of  the  burrow.  After  the  burrow  is  completed,  and  the 
eggs  laid,  the  entrance  to  the  nest  is  carefully  filled  up  with 
clay,  or  dirt,  moistened  with  fluid  from  the  mouth. 

117.  It  has  been  learned,  in  studying  the  development  of 
the  insect  proper,  that  the  worm-like  larva  comes  from  the 
egg  with  its  full  number  of  rings  or  segments,  and  that,  as 
the  creature  matures,  some  of  these  segments  are  so  merged 
into  other  parts,  particularly  with  some  of  the  caudal  ones, 
that  it  seems  as  if  the  perfect  insect  has  a  less  number  of 
rings  than  the  larva.  In  the  myriapods,  however,  the  young 
creature  as  it  hatches  from  the  egg  possesses  only  a  few  seg- 


FIG.   119.— HIGHLY-MAGNIFIED  FIGURE  OP  A  VERY  YOUNG  MILLEPEDE,  SHOBTLY  AFTEB 

HATCHING  FROM  THE  EGG. 

(Eeduced  from  a  figure  by  Elias  Metschnikoff.) 

ments,  but  as  it  grows,  new  segments  are  from  time  to  time 
formed  near  the  hinder  part  of  the  body,  until  the  creature 


128  FIRST  BOOK  OF  ZOOLOGY. 

attains  adult  size,  when  it  may  possess  over  a  hundred  seg- 
ments. 

Like  true  insects,  the  young  myriapod  makes  its  appear- 
ance from  the  egg  with  three  pairs  of  legs.  The  body,  how- 
ever, is  never  divided  into  a  thoracic  portion,  and  an  abdomi- 
nal portion,  as  in  the  true  insects,  or  into  two  regions  as  in 
the  spiders,  but  after  the  head  there  succeeds  a  continuous 
row  of  similar  segments  to  the  tail. 

118.  In  studying  the  insects,  spiders,  and  centipedes,  or 
myriopods,  the  pupils  have  learned  something  about  three 
groups  of  animals  which  have  in  common  a  body  composed 
of  segments,  and  possessing  jointed  legs.  They  all  breathe 
air  through  holes  in  the  side  of  the  body,  called  spiracles, 
the  air,  thus  breathed,  finding  its  way  through  various  parts 
of  the  body  by  means  of  little  tubes  called  trachese,  except  in 
the  spiders,  where  little  sacs,  called  pulmonary  sacs,  take  the 
place  of  trachese. 

In  the  true  insects  the  segments  of  the  body  are  gathered 
into  three  regions,  called  respectively  the  head,  thorax,  and 
abdomen.  In  the  spiders  the  segments  of  the  body  are  gath- 
ered into  two  regions,  called  respectively  the  cephalo-thorax, 
and  abdomen,  the  head  being  merged  in  the  thorax.  In  the 
myriapods  the  head  is  again  distinct  as  in  the  true  insects, 
but  the  remaining  segments  of  the  body  are  distinct  and  are 
not  grouped  into  regions. 

The  true  insects  have  three  pairs  of  legs.  The  spiders 
have  four  pairs  of  legs,  while  the  myriapods  have  no  definite 
number  of  legs.  In  some  species  there  are  nearly  two  hundred 


DADDY-LONG-LEGS,  CENTIPEDES,  AND  MILLIPEDES.       129 

pairs  of  legs,  and  in  no  species  are  there  less  than  ten  pairs  of 
legs.  The  true  insects  alone  have  wings. 

119.  In  the  growth  or  development  of  the  true  insects 
and  spiders,  the  young  animal  conies  from  the  egg  with  its 
full  number  of  segments  complete,  while  in  the  myriapods 
the  young  animal  comes  from  the  egg  with  a  few  segments, 
and  new  ones  are  added  as  the  animal  grows. 

Some  of  the  characters  of  the  insects,  spiders,  and  myri- 
apods,  may  be  represented  as  follows : 


i 

Three  pairs  of  legs,  and  having  wings. 
TRUE  INSECT.— Body  divided  into  Three  Eegions. 


12  34 

Four  pairs  of  legs. 
8pn>EB.--Body  divided  into  Two  Regions,  Head  not  separate. 


nvm 

No  definite  number  of  legs 

MTRIOPOD.— Body  not  divided  into  Eegions,  but  Head  separate. 
FIG.  120.— ANIMALS  WHOSE  BODIES  ARE  COMPOSED  OP  SEGMENTS  POSSESSING  JOINTED  LEGS, 

AND   BREATHING   AlR  THROUGH   OPENINGS   IN  THE   SlDES  OF  THE   BODY. 

On  account  of  some  of  these  characteristics  above  men- 
tioned, with  others  not  mentioned,  being  held  in  common  by 
the  true  insects,  spiders,  and  myriapods,  these  creatures  form 
a  natural  group  in  the  animal  kingdom,  just  as  the  snails, 


130  FIRST  BOOK  OF  ZOOLOGY. 

mussels,  oysters,  and  clams,  possessing  certain  characters  in 
common,  together  form  a  natural  group  of  animals. 

There  are,  however,  many  other  animals  which  are  not 
insects,  spiders,  or  myriapods,  and  still  possess  a  body  com- 
posed of  segments,  and  also  have  jointed  legs,  and  these  ani- 
mals are  to  furnish  the  subject  for  the  next  lesson. 


CHAPTER  XVII. 

CRAWFISH     AND     LOBSTER. 

120.  THE  fresh-water  Crawfish,  or  fresh-water  Lobster  as 
it  is  sometimes  called,  is  very  common  in  many  of  the  West- 
ern rivers.  It  may  be  collected  in  little  pools  by  the  river- 
side, and  kept  alive  for  a  long  while  in  a  jar  of  water.  It 
may  be  fed  on  fresh-water  snails  and  the  larvae  of  insects. 
It  would  be  well  to  keep  the  animal  alive  for  a  while,  so 
that  its  motions  in  swimming  and  crawling  may  be  ob- 
served. For  the  cabinet,  it  can  be  dried  with  the  legs  out- 
stretched, or  specimens  may  be  preserved  in  alcohol. 

The  general  form  of  the  body  is  much  like  that  of  the 
salt-water  lobster,  differing,  however,  greatly  in  size;  the 
crawfish  varying  from  three  to  five  inches  in  length,  and 
the  lobster  attaining  a  much  larger  size. 

The  animal  is  divided  into  two  regions,  the  body  proper, 
to  which  the  legs  and  big  claws  are  attached,  and  the  abdo- 
men, -consisting  of  the  jointed  portion  behind.  The  head 


CRAWFISH  AND   LOBSTER. 


131 


does  not  appear  separated  from  the  body  as  in  the  insects, 
but  is  combined  with  the  thorax,  and  hence  this  part  is  called 
the  cephalo-thorax,  as  in  the  spiders.  The  cephalo-thorax  is 
covered  by  a  continuous  shield,  or  shell,  called  the  carapace, 
while  the  abdomen  is  divided  into  a  series  of  segments.  This 
part  can  be  bent  snugly  beneath  the  body  (see  Fig.  121). 


FIG.  121.— FRESH-WATER  CRAWFISH  FROM  THE  MISSISSIPPI  EIVER. 

At  the  hinder  end  of  the  abdomen  are  five  flattened  ap- 
pendages, which  serve  as  fins,  by  means  of  which  the  animal 
can  swim  vigorously  backward.  (See  Fig.  122.) 


FIG.  122.— TAIL  OF  CRAWFISH  SHOWING  FLATTENED  APPENDAGES  FOR  SWIMMING. 

There  are  two  compound  eyes  in  front,  which  rest  upon 
little  jointed  stalks,  so  that  the  creature  can  turn  them  in 
various  directions. 


132  FIRST  BOOK  OF  ZOOLOGY. 

121.  Just  below  the  eyes  are  two  long,  and  two  short  and 
double  antennae,  or  feelers,  and  directly  below  these  are  six 
pairs  of  variously  shaped  and  jointed  appendages  closely 
packed  together.     They  surround  the  mouth  and  assist  in 
securing  and  preparing  the  food  for  the  stomach.     The  first 
pair  are  called  jaws,  or  mandibles,  and  are  furnished  with 
sharp  cutting  edges  for  biting  the  food,  and  a  flattened  sur- 
face for  grinding  or  crushing  it.     The  next  two  pairs  are 
called  maxillce,  and  are  accessory  jaws.     The  pair  of  mandi- 
bles and  the  two  pairs  of  maxillae,  with  another  pair  just 
behind,  making  four  pairs  in  all,  belong  to  the  head,  the 
other  two  pairs  of  mouth-parts  belong  to  the  thorax,  and  are 
so  evidently  modified  claws  or  feet  that  they,  with  the  pair 
just  in  front  of  them,  are  called  foot-jaws  or  maxillipedes. 
(See  Fig.  126,  in  which  these  parts  are  all  named.) 

122.  From  the  under  side  of  the  body  project  five  pairs 
of  jointed  legs,  and  these  differ  in  shape  and  size.     The  first 
pair  are  much  larger  than  the  rest,  and  in  the  lobster  are 


a 

FIG.  128.— A  Bio  CLAW  OF  THE  LOBSTER,  SHOWING  THE  WOODEN  WEDGE,  a. 

called  the  big  claws.  *  They  carry  at  their  extremities  big 
pincer-like  jaws  capable  of  giving  a  sharp  nip,  and  which 
are  used  as  weapons  of  defense,  and  also  to  hold  on  to  their 
prey.  The  lobster  can  bite  very  severely  with  these  big 


CRAWFISH  AND   LOBSTER.  ^33 

claws,  and  for  this  reason  the  fisherman  drives  in  a  little 
wedge  of  wood  to  prevent  the  animal  from  opening  the  mov- 
able part,  so  that  he  can  handle  it  without  being  bitten. 

The  other  legs  are  long  and  slender.  The  two  forward 
pairs  end  in  slender  nippers,  while  the  two  hinder  pairs  end 
in  a  single  projecting  claw.  With  these  four  smaller  pairs 
of  legs  the  crawfish  and  lobster  crawl  or  walk. 

On  the  under  side  of  the  abdomen  are  little  flattened  ap- 
pendages arranged  in  pairs,  a  pair  to  each  ring  or  segment. 
The  animal  not  only  swims  backward  by  means  of  the  broad 


Fio.  124.— ONE  OP  THE  FLATTENED  OR  ABDOMINAL  APPENDAGES  OP  A  LOBSTER. 

fins  on  the  end  of  the  tail,  or  abdomen,  but  has  the  power 
besides  to  swim  in  a  forward  direction  by  extending  the  ab- 
domen, and  using  the  little  fins  below  as  swimming  organs. 

123.  The  crawfish,  like  the  lobster,  breathes  in  the  water 
by  means  of  gills.  These  are  attached  to  the  base  of  the 
legs  and  are  concealed  on  the  sides  of  the  thorax  by  the 
carapace,  which  covers  them.  By  forcibly  tearing  up  the 
side  of  the  carapace,  there  will  be  exposed  the  gills  which 


134 


FIRST  BOOK  OF  ZOOLOGY. 


look  like  plumes.  This  space  may  "be  called  the  gill-chamber, 
and  the  water  flows  into  it  by  passing  under  the  edge  of  the 
carapace  back  of  the  big  claws,  and  passes  out  of  an  opening 
near  the  mouth-parts.  The  currents  of  water  flowing  in  to 
the  gill-chamber  are  induced  by  a  stiff  appendage  attached  to 
the  base  of  the  second  pair  of  maxillae  called  the  fldbellum 
(see  Fig.  125),  and  which  swings  back  and  forth  and  scoops 
the  water  into  this  chamber.  These  gills  are  shown  as  they 
appear  in  the  crawfish.  In  tearing  off  the  claws  of  the 
lobster,  the  gills  are  often  drawn  out  too,  and  remain  attached 
to  the  base  of  the  legs.  In  the  lobster  the  carapace  can  be 
easily  bent  up,  so  as  to  show  the  gills. 

In  the  following  figure  a  crawfish  is  shown  with  a  portion 

cepJialo-thorax  abdomen 


ill  antenna 

large  antenna 

indible 
maxilla 

cittipedes)  2- 

(a— 


C     f  B  A 

FIG.  125.— CRAWFISH  SEEN  FROM  THE  SIDE,  WITH  THAT  PORTION  OF  THE  CARAPACE  REMOVED 
WHICH  COVERS  THE  BRANCHIAE  OR  GlLLS.  THE  APPENDAGES  OF  THE  LEFT  SIDE  ONLY 
SHOWN.— -8,  Kegion  of  Stomach;  A,  Abdominal  Appendages;  £,  Bases  of  the  Four  Small 
Legs:  <7,  Base  of  Large  Claw;  /;  Flabellum  attached  to  the  Second  Maxillipede;  e,  Eye. 


CRAWFISH  AND   LOBSTER.  135 

of  the  carapace  on  the  left  side  removed  to  show  the  gills  as 
they  appear  in  the  gill-space.  The  big  claw  and  the  four 
smaller  claws  or  legs  are  cut  off,  so  that  the  other  parts  can 
be  plainly  shown. 

124.  If  the  pupils  are  skillful  enough,  it  will  be  a  good 
exercise  for  them  to  separate  the  various  appendages  of  the 
crawfish,  and  arrange  them  upon  a  card,  just  as  the  beetle 
was  arranged,  as  shown  on  page  66,  fastening  the  carapace 
in  the  middle  of  the  card  with  the  back  uppermost,  then 
gluing  the  abdomen  to  the  card,  or,  if  possible,  separating 
each  ring  of  the  abdomen  and  gluing  each  one  separately  to 
the  card,  one  behind  the  other,  and  then  arranging  the  ap- 
pendages on  each  side  of  the  thorax  and  abdomen,  and  with 
a  pen  marking  the  names  of  the  various  parts  on  the  card. 

Figure  126  represents  the  way  in  which  the  mouth-parts 
of  a  crawfish  or  lobster  may  be  arranged. 

As  the  lobster  is  a  much  larger  animal  than  the  craw- 
fish, it  will  be  easier  to  separate  its  appendages,  and  these 
may  as  well  be  taken  from  a  specimen  which  has  already 
been  boiled,  or  as  it  may  be  obtained  in  the  market.  They 
may  then  be  dried  and  fastened  to  a  card  with  glue.  The 
red  color  of  the  lobster  appears  only  when  the  animal  is 
boiled.  When  alive  the  color  of  the  creature  is  a  reddish- 
yellow  mottled  with  bluish  or  greenish-black. 

125.  The  eggs  are  carried  by  the  crawfish  and  lobster 
glued  in  masses  to  the   swimming   appendages  which   are 
attached  to  the  lower  surface    of    the    abdomen,  and   the 
creatures  retain  them  in  this  way  till  the  young  hatch  .out. 


136 


FIRST  BOOK  OF  ZOOLOGY. 


This  feature  is  characteristic  of  the  class  to  which  these  ani- 
mals belong.  How  different  in  this  respect  from  the  creat- 
ures already  studied,  in  which  the  eggs  are  deposited  and 
left  by  the  animal !  It  has  been  learned  that  certain  spiders 
too  carry  their  eggs  round  with  them,  and  protect  them. 


BITING -JAW  . . 


LITTLE  JAWS  OB  ACCKS 

BORY  JAWS,   OK  MAXIL- 


FOOT-JAWS,     OR     MAXTL 
LIPKDE8. 


MandilU.... 
First  Maxilla 
^  Second  Maxilla 

f  First  Maxilliped 
Second  Maxilliped, 
Tldrd  Maxilliped 
FIG.  126.— MOUTH-PARTS  OF  A  CRAWFISH  FROM  THE  LEFT  SIDE. 

Fig.  128  represents  a  crab  carrying  its  eggs  glued  to  the 
appendages  on  the  under  surface  of  the  abdomen.  Pupils 
having  access  to  lobsters  in  the  markets,  will,  by  looking  over 
them,  find  some  specimens  in  which  the  eggs  are  being  carried 
in  this  way. 

126.  The  young  animal  in  growing  sheds  its  entire  shell, 


CRAWFISH  AND  LOBSTER.  137 

in  this  respect  again  resembling  the  spider.  This  process  is 
called  moulting,  a  term  used  in  describing  a  similar  process 
in  the  spider.  The  lobster  and  crawfish  continue  to  shed 
their  shells  at  different  periods,  till  they  attain  full  growth. 
It  is  stated  that  the  crawfish  sheds  its  shell  annually.  If  the 
pupils  will  keep  some  of  these  creatures  alive,  they  will  prob- 
ably have  an  opportunity  to  observe  this  curious  process  of 
moulting,  in  which  the  entire  outer  skin,  or  shell,  is  discarded, 
so  that  there  is  left,  complete  in  all  its  parts,  the  empty  crust, 
like  a  discarded  garment.  The  carapace  separates  from  the 
abdomen  above  and  cracks  along  the  back,  and  by  a  series  of 
efforts  the  animal  pulls  its  way  out.  Great  trouble  is  expe- 
rienced in  withdrawing  the  legs,  and  oftentimes  a  leg  is  left 
behind,  and  cases  are  recorded  wherein  the  animal  has  perished 
in  the  straggles  to  liberate  itself  from  the  old  skin.  For 
some  time  the  animal  shows  great  timidity,  and  the  lobster, 
when  it  has  freshly  shed  its  skin,  retires  to  some  secluded 
place,  and  there  remains  till  the  soft  and  tender  skin  has 
become  thickened  and  hardened,  so  as  to  enable  it  to 
withstand  the  attack  of  its  enemies.  Lobsters  often  lose 
their  legs  in  fighting,  and  on  a  sudden  alarm  are  capable  of 
dropping  them  off.  The  loss  of  the  leg  in  this  way  is  made 
good  by  the  curious  property  the  stump  has  of  reproducing 
another  leg,  which  grows  out  again,  jointed  and  shaped  like 
the  one  lost,  only  much  smaller  than  the  original  one.  At 
each  succeeding  moult,  however,  the  leg  becomes  larger  and 
larger.  If  the  pupils  will  now  carefully  examine  a  lot  of 
lobsters,  they  will  notice  among  them  some  specimens  in 


138  FIRST  BOOK  OF  ZOOLOGY. 

which  some  one  of  the  legs  will  be  much  smaller  than  its 
mate  on  the  other  side.  This  shows  where  a  new  leg  has 
grown,  to  replace  one  previously  lost. 

127.  The  young  passes  through  a  remarkable  series  of 
moults,  or  shedding  of  the  shell,  and  each  moult  brings  it 
nearer  in  appearance  to  the  general  form  of  a  lobster.  The 
following  figure  presents  the  appearance  of  a  young  lobster 
which  has  undergone  several  such  moults. 


FIG.  127.— A  YOUNG  LOBSTER  MAGNIFIED.— a  shows  the  Natural  Size  of  the  Creature. 
(Reduced  from  a  Figure  drawn  by  Sidney  I.  Smith.) 


CHAPTEK  XVIII. 

CKABS,    HERMIT-CRABS,   AND   OTHEK   CRUSTACEANS. 

128.  THE  class  of  animals  to  which  the  crawfish  and 
lobster  belong  is  called  Crustacea,  a  name  derived  from  a 
Latin  word,  crusta,  meaning  a  crust,  or  the  shell  with  which 
the  animals  of  this  class  are  covered. 

To  this  class  belong  the  crabs,  hermit-crabs,  shrimps, 
and  an  infinite  variety  of  forms  found  in  salt-water,  certain 
little  creatures  found  in  the  great  lakes  and  other  fresh 


CRABS,  HERMIT-CRABS,  AND   OTHER  CRUSTACEANS.      139 

waters,  as  well  as  a  little  creature  known  as  the  sowbug,  which 
is  common  under  stones  and  boards  in  damp  places.  By  far 
the  larger  proportion  of  these  animals  are  found  in  salt-water. 

Pupils  having  access  to  the  sea-coast  will  find  along  the 
shore,  and  in  pools  of  water  left  at  low  tide,  a  number  of 
species  unlike  any  thing  found  in  fresh  water. 

The  common  crab  may  be  studied  and  compared  with 
the  lobster.  It  will  be  found  that  the  crab  has  the  large 
claws,  little  legs,  mouth-parts,  antennae,  and  other  details 
similar  to  the  lobster  and  crawfish.  The  body,  however, 
is  entirely  unlike  in  shape ;  instead  of  being  long  and  cylin- 
drical, it  is  wide  and  flattened,  and  the  long,  jointed  abdomen 
so  characteristic  of  the  lobster  and  crawfish  is  quite  concealed 
in  the  crab.  At  first  sight,  the  creature  would  appear  to 
have  no  portion  corresponding  to  this  part  in  the  lobster, 
but  beneath  the  body  there  will  be  found  a  close-fitting  piece 
composed  of  segments  or  joints,  and,  if  this  be  raised  or 
opened,  the  relation  between  this  small  piece  and  the  large 
jointed  abdomen  of  the  lobster  becomes  at  once  apparent. 

The  crab  carries  her  eggs  attached  in  masses  to  the  ab- 
dominal appendages  which  are  arranged  in  pairs  on  the 
segments  of  the  abdomen,  as  in  the  lobster. 

In  the  following  figure,  which  represents  a  crab  carrying 
her  eggs,  a  comparison  of  parts  may  be  made  between  it  and 
the  crawfish  or  lobster. 

The  eggs  as  they  are  laid  are  covered  with  a  sticky  fluid, 
which  thickens  into  threads  and  holds  the  eggs  together  and 
also  holds  them  in  masses  to  the  abdominal  appendages. 


140 


FIRST  BOOK  OF  ZOOLOGY. 


These  appendages,  having  long  hairs,  retain  the  eggs  all  the 
more  securely. 


FIG.  128.— SIDE- VIEW  OP  COMMON  CRAB,  WITH  THE  ABDOMEN  EXTENDED  AND  CARRYING  A 
MASS  OF  EGGS  BENEATH.— e,  Eggs. 

Under  the  microscope  the  eggs  appear  like  bunches  of 
berries  or  currants.  The  following  figure  represents  a  few 
eggs  from  a  common  crab : 

A  B 


Fro.  129. — A,  a  few  Eggs  from  a  Common  Crab,  enlarged ;  B,  Single  Egg  greatly  enlarged, 
showing  more  plainly  the  hardened  Thread  tf,  by  which  they  are  attached  to  each  other. 
This  Egg  shows  the  young  crab  just  beginning  to  form. 

129.  The  small  legs  of  a  crab  terminate  in  a  single  claw. 
There  are  no  nipper  or  pincer-like  ends  as  in  the  two  forward 


CRABS,  HERMIT-CRABS,  AND  OTHER  CRUSTACEANS.      141 

pairs  of  claws  of  the  lobster,  and  in  studying  the  crustaceans 
generally  an  infinite  variety  of  modification  will  be  found  in 
these  parts.  In  the  crab  which  is  so  much  sought  after  for 
food,  and  which  is  known  as  the  soft-shell  crab  (a  condition 
which  indicates  that  the  crab  has  just  moulted,  or  shed  its 
hard  shell),  the  hinder  pair  of  legs  have  the  last  or  terminal 
joints  flattened,  and  these  flattened  joints  are  used  as  fins  by 
means  of  which  the  creature  swims  through  the  water. 


FIG.  130.— EIGHT  HIND-LEG  OP  THE  EDIBLE  CRAB. 

The  above  figure  shows  the  appearance  of  the  right 
hind-leg  of  one  of  these  crabs.  Compare  this  with  the  com 
mon  crab  shown  in  Fig.  128. 

130.  A  curious  little  crab,  called  the  oyster-crab,  makes  its 
home  within  the  shell  of  the  oyster,  living  in  the  gill-cavity 


FIG.  131.— OYSTER-CBAB.    The  Tail  is  hidden  beneath  the  Body,  one  Segment  only  showing. 

of  the  animal.  Specimens  may  sometimes  be  found  in 
canned  oysters,  and,  to  those  who  do  not  have  access  to  the 
sea-shore,  these  creatures  will  furnish  objects  from  which 
an  idea  of  the  crabs  or  short-tailed  crustaceans  may  be 


142  FIRST  BOOK  OF  ZOOLOGY, 

obtained.  The  tail  will  be  found  flattened  against  the  under 
side  of  the  body.  Another  species  occurs  in  the  salt-water 
mussel. 

In  the  female  crab,  a  figure  of  which  is  given  (128), 
this  part  is  very  large  and  will  be  oftentimes  found  holding 
a  mass  of  eggs.  With  care  the  creatures  may  be  dried, 
and  their  various  parts  separated  and  stuck  upon  cards  for 
the  cabinet. 


FIG.  132.— HEBMIT-CBAB  IN  THE  SHELL  OF  A  SEA-SNAIL. 

131.  The  hermit-crab  possesses  the  general  features  of  the 
common  crab  and  lobster.  The  abdominal  portion  is  long 
and  cylindrical,  and,  instead  of  being  encased  in  a  hardened 
shell  as  in  fche  lobster,  it  is  soft  and  pliant,  with  scarcely  a 
trace  of  hardened  parts  to  indicate  the  segments.  The  creat- 
ure, having  this  defenseless  part,  protects  itself  by  securing 

the  hard  shell  of  some  sea-snail  as  a  house  in  which  it  con- 

• 

stantly  lives.     The  caudal  appendages  are  curiously  modified 


CRABS,  HERMIT-CRABS,  AND  OTHER  CRUSTACEANS.      143 

to  enable  it  to  retain  its  hold  on  the  shell,  and  the  other  ab- 
dominal appendages  are  rudimentary  or  wanting  on  the  right 
side,  or  that  side  which  comes  most  against  the  inside  of  the 
shell,  as  if  they  had  been  worn  off.  Wherever  the  creature 
goes,  it  draffs  the  shell  after  it  as  a  house. 

O  "  O 


FIG.  133.— HEEMIT-CRAB  REMOVED  FROM  ITS  SHELL:  r,  Hardened  Ridge  which  bears  against 
the  Inner  Edge  of  the  Aperture  of  the  Shell ;  a,  a,  Appendages  to  which  the  Eggs  are 

attached. 

• 

As  the  hermit-crab  grows,  it  passes  through  the  same 
features  of  moulting  which  characterize  the  crustaceans  gen- 
erally. The  shell  which  protects  its  soft  defenseless  abdomen 
has,  of  course,  no  power  of  growth,  and  is  abandoned  when 


144  FIRST  BOOK  OF  ZOOLOGY. 

the  hermit-crab  gets  too  big  for  it.  The  creature  has,  there- 
fore, to  go  in  search  of  another  house  slightly  bigger  than 
the  one  ready  to  be  discarded.  It  is  said  that  it  does  not 
always  content  itself  with  the  dead  shells  that  strew  the 
beach,  but  has  been  seen  attacking  a  live  snail  and  eating  it 
for  the  purpose  of  occupying  its  vacant  shell,  and  this  is 
rendered  probable  by  the  fact  that  they  so  often  occupy 
fresh  and  perfect  shells. 

Not  unfrequently  they  are  found  living  in  old  and  beach- 
worn  shells  which  they  have  dragged  about  so  long  as  to 
have  worn  the  shell  nearly  through  at  the  place  where  it 
rests  and  nibs  against  the  sand.  The  pupils  may  collect 
hermit-crabs  of  all  sizes* on  the  shores. 

The  figure  on  the  preceding  page  represents  a  hermit- 
crab  after  its  removal  from  the  shell.  The  creature  is 
drawn  as  it  appears  lying  on  its  back. 

132.  There  are  comparatively  few  species  of  crustaceans 
found  in  fresh  water ;  and,  with  the  exception  of  the  species 
of  crawfish  and  a  few  others,  the  fresh-water  crustaceans  are 
of  small  size. 


FIG.  184.— FRESH-WATER  CRUSTACEAN.    The  Line  below  represents  the  Natural  Length  of 

the  Animal. 

(Reduced  from  a  Figure,  in  8. 1.  Smith's  Eeport,  of  Fresh- Water  Crustacea,  published  by  U. 
S.  Fish  Commission.) 


CRABS,  HERMIT-CRABS,  AND   OTHER  CRUSTACEANS.      145 

The  figure  134  represents  a  small  species  which  is  com- 
mon in  stagnant  pools  in  nearly  all  the  Northern  States. 

From  this  species  the  pupils  may  study  a  form  in  which 
the  segments  of  the  thorax  are  not  covered  by  a  continuous 
shield. 

The  sowbug  is  a  crustacean  which  lives  out  of  water, 
though  always  requiring  damp  surroundings.  It  may  be 
collected  under  logs  and  stones.  In  this  creature  the  seven 
segments  of  the  thorax  are  easily  counted. 


FIG.  135.— COMMON  SOWBUG.— The  line  shows  the  length  of  the  specimen  from  which  this 

figure  was  made. 

The  eggs  of  the  sowbug,  as  well  as  those  of  other  species 
of  crustaceans  of  the  same  group,  are  carried  on  the  under 
side  of  the  thorax  and  between  the  legs,  in  a  little  brooding 
cavity  made  by  leaf-like  parts  which  lap  over  each  other 
and  hold  the  eggs  in  place. 

The  eggs  of  these  crustaceans  may  be  found  by  examin- 
ing the  under  side  of  the  body,  and  observing  a  lightish- 
colored  space  between  the  legs.  With  a  pin  or  the  point 
of  a  knife-blade  they  may  be  scraped  away  without  injuring 
the  animal.  They  are  very  minute,  and  only  under  the 


146  FIRST  BOOK  OF  ZOOLOGY. 

microscope  can  the  development  of  the  young  creature  be 
watched.  The  following  figure  represents  a  single  egg  of 
the  sowbug  highly  magnified : 


FIG.  136.— EGG  OF  SOWBUG,  HIGHLY  MAGNIFIED.— The  little  dot,  at  one  side,  represents  the 
natural  size  of  the  egg.    The  head  faces  the  left. 

Around  the  upper  edge  of  the  embryo  (as  a  young  animal 
in  the  egg  is  called),  from  eighteen  to  twenty  little  blunt  ap- 
pendages may  be  seen;  these  represent  the  legs  and  other 
appendages  of  the  body — the  one  longer  than  the  rest  is  an 
antenna.  As  the  creature  grows,  these  appendages  become 
jointed  and  variously  modified  to  form  the  legs,  mouth-parts, 
antennae,  and  the  appendages  on  the  tail,  which  differ  greatly 
from  each  other,  though  at  the  outset  they  are  all  alike. 

133.  Having  studied  a  few  of  the  many  different  kinds 
of  crustaceans,  let  the  pupils  examine  them  together  to  find 
some  points  characteristic  of  them  all. 

Their  bodies,  in  common  with  the  insects,  are  composed 
of  segments  to  which  are  attached  jointed  appendages  of 
various  kinds.  This  body  is  divided  into  two  regions,  the 
cephalo-thorax  and  the  abdomen.  In  some  the  cephalo-thorax 
is  covered  by  a  continuous  shield,  called  the  carapace,  as  in 
the  crawfish,  crab,  lobster,  and  shrimp.  In  others  the  seg- 
ments of  the  cephalo-thorax  are  distinctly  separate,  and 
movable  upon  each  other,  as  in  the  sowbug  and  certain  other 


BIVALVE   CRUSTACEANS  AND  BARNACLES. 


147 


crustaceans,  one  of  which  is  figured  on  page  145.  The  ceph- 
alo-thorax  is  composed  of  fourteen  segments,  seven  of  these 
belonging  to  the  head,  judging  from  the  number  of  append- 
ages which  arise  from  that  part.  The  abdomen  is  supposed 
to  possess  seven  segments,  though  the  last  one  is  so  rudimen- 
tary that  its  existence  as  a  true  segment  has  been  denied  by 
some. 

The  deep  line  running  across  the  back  of  the  carapace,  in 
the  crawfish  and  lobster,  is  called  the  cervical  suture. 

The  following  outline  represents  a  sowbug,  with  the 
regions  of  the  body  marked.  Compare  this  with  Fig.  125. 

head, 
tliorax- 

abdomen. 
FIG.  137.— SOWBUG,  WITH  REGIONS  OF  BODY  MASKED. 


CHAPTER  XIX. 

BIVALVE   CRUSTACEANS   AND  BARNACLES. 

134.  THE  crustaceans  during  their  growth  shed  their  hard 
outer  covering  at  intervals,  and,  in  this  as  in  many  other  re- 
spects, resemble  the  spiders.  In  the  possession  of  gills,  in- 


148  FIRST  BOOK   OF  ZOOLOGY. 

stead  of  air-cavities,  the  crustaceans  show  a  marked  difference 
between  themselves  and  spiders. 

Now,  there  are  hundreds  of  minute  crustaceans  in  which 
it  would  be  hard  to  recognize  any  close  relations  between 
them  and  the  crustaceans  already  studied. 

Among  these  odd  forms  may  be  mentioned  certain  little 
animals  abundant  in  ditches  and  pools  throughout  the  coun- 
try. Some  of  these  creatures  are  smaller  than  a  pin's-head  ; 
others  are  as  large  as  an  ordinary  white  bean. 

At  first  sight  they  might  readily  be  mistaken  for  bi- 
valve mollusks,  as  the  body  is  covered  with  a  bivalve  shell, 
which  partly  opens  and  shuts,  and  is  firmly  attached  to 
the  body  within.  If  the  pupils  are  fortunate  enough  to 
collect  some  of  these  creatures  in  a  net  and  watch  them  as 
they  actively  dart  about  in  a  jar  of  water,  they  will  at  once 
see  the  difference  between  them  and  the  clam  or  mussel. 

Instead  of  the  animal's  projecting  a  soft  and  fleshy  foot 
with  which  to  creep  slowly  along,  as  in  the  mussels,  they  will 
see  numbers  of  little  jointed,  swimming  legs  partly  protruded, 
and  jointed  antennae  thrust  out  in  front ;  and,  if  their  eyes 
are  keen  enough,  may  detect  a  little  black  speck  just  above 
the  antennae,  which  represents  the  eye. 

The  following  figures  represent  a  species  collected  in 
Dubuque,  Iowa,  and  another  form  from  Lynn,  Massachusetts. 

135.  The  concentric  lines  on  the  shell  appear  like  lines 
of  growth,  and  such  they  really  are ;  but  they  are  not  made 
like  the  lines  of  growth  on  the  mussel.  When  the  creature 
moults,  the  delicate  skin  covering  the  antennre  and  swim- 


BIVALVE   CRUSTACEANS  AND  BARNACLES. 


149 


ming  legs  is  discarded.  The  moulting  process  also  takes 
place  with  the  bivalve  shell,  but,  instead  of  its  being  dis- 
carded, the  inoult  is  held  or  cemented  to  the  new  shell  which 
forms  underneath.  Moult  after  moult  of  the  shell  is  thus 
retained,  the  increasing  size  of  each  moult  showing  as  sep- 


FIG.  138.— FRESH- WATER  CRUSTACEANS;  D,  Species  from  Dubuque,  Iowa;  «,  Eye.  The  line 
below  indicates  the  natural  length  of  the  specimen ;  Z,  Species  from  Lynn,  Mass. :  this  is 
figured  the  natural  size ;  S  presents  a  highly-magnified  section  of  one  of  the  shells,  to 
show  the  successive  moults,  these  being  numbered  in  their  order  of  moulting ;  B  shows 
the  appearance  of  a  portion  of  the  edge  of  the  shell  along  the  back,  representing  the  succes- 
sive moults  lapping  one  over  the  other. 

arate  concentric  lines  of  growth.  If  the  shell  is  cut  into 
and  the  cut  edge  is  examined  with  a  microscope,  the  succes- 
sive moults  will  be  seen  resting  one  upon  the  other,  like  the 
leaves  of  a  book.  By  reading  carefully  the  description  ac- 
companying Fig.  138,  the  pupils  will  learn  more  about  it. 

The  very  young  stages  of  these  creatures  have  some 
resemblance  to  the  young  of  the  barnacle  shown  in  Fig.  141. 

136.  Another  group  of  animals  classed  with  the  Crustacea 
is  still  more  unlike  the  forms  already  studied.  These  are 


150 


FIRST  BOOK   OF  ZOOLOGY. 


the  barnacles.  They  are  found  in  immense  numbers  cover- 
ing the  rocks  and  piers  in  places  between  high  and  low 
water  mark.  In  nearly  all  places  along  the  coast  the  rocks 
are  whitened  by  their  numbers.  Pupils  living  inland  can 
get  specimens  of  the  barnacle  by  visiting  places  where  oys- 
ters are  received  in  the  shell ;  and,  by  examining  the  shells 
as  they  are  thrown  away,  may  now  and  then  come  across 
good  specimens.  "With  a  stiff  brush  and  some  water  the 
mud  may  be  washed  off  the  shell,  and  then  the  creature  will 
present  the  following  appearance. 


FIG.  139.— BAENACLE  ON  OYSTER-SHELL.— The  circular  scar  on  the  shell  indicates  the  place 
from  which  another  barnacle  had  been  taken. 


The  barnacle-shell  is  round  and  conical,  broad  at  the 
base  by  which  it  is  firmly  attached  to  the  rock  or  whatever 
object  it  grows  upon.  The  walls  of  this  shell  are  composed 
of  six  pieces  whose  edges  overlap  each  other.  The  opening 
in  the  top  of  the  shell  is  closed  by  four  plates  which  tightly 
fit  together. 

In  collecting  these  creatures  for  the  purpose  of  studying 
them  alive,  care  must  be  taken  in  breaking  them  from  the 


BIVALVE   CRUSTACEANS  AND  BARNACLES.  151 

rock.  It  will  be  much,  better  to  take  them  from  the  wooden 
piers,  or,  if  possible,  specimens  should  be  collected  attached 
to  some  pebble.  These  may  now  be  placed  in  a  jar  or  bowl 
of  salt-water ;  and,  if  they  are  watched  closely,  there  will  be 
seen  a  set  of  fringed  arms,  like  hairs,  thrust  out  at  the  top  of 
the  shell,  which,  stretching  out  with  graceful  curves,  close  and 
partly  retract  within  the  opening.  This  motion  will  be  con- 
stantly and  rapidly  repeated.  There  are  six  pairs  of  these 
appendages,  and  they  are  flung  out  in  this  way  to  grasp  the 
minute  particles  in  the  water,  which  serve  them  as  food. 
The  arms  being  jointed  and  fringed  with  delicate  hairs,  the 
whole  combined  forms  a  sort  of  net.  In  Fig.  140,  (7,  the 
tip  of  one  of  these  arms  is  shown,  highly  magnified. 


FIG.  140.—^!,  Side-View  of  Barnacle,  Natural  Size,  showing  Appendages  protruded  for  Food; 
-B,  Top-View  of  same  closed ;  (7,  highly-magnified  View  of  the  Tip  of  one  of  the  Appendages. 

137.  Inland  pupils  may  break  open  the  barnacles  collected 
on  the  oyster-shell,  and,  taking  out  the  soft  parts,  may  examine 
them  by  placing  the  parts  in  water,  when  the  fringed  arms 
become  apparent ;  and  under  the  microscope  the  delicate  hairs 


152 


FIRST  BOOK   OF  ZOOLOGY. 


which  fringe  the  arms  may  be  seen.  The  jointed  structure 
of  these  appendages  and  their  arrangement  in  pairs  show 
that  the  creature  does  not  belong  to  the  shell-fish  or  mol- 
lusks, as  its  shell  might  seem  to  indicate. 

In  past  times  many  able  naturalists  classed  these  creat- 
ures with  the  mollusks,  because  they  judged  from  the  ex- 
ternal appearances  of  the  shell,  which  was  limy.  A  careful 
study  of  their  anatomy  and  development  proved  their  rela- 
tions to  the  crustaceans,  and  that  they  had  no  affinities  what- 
ever with  the  mollusks.  In  their  growth  they  moult,  in  this 
act  shedding  all  the  skin,  and  at  certain  times  in  the  summer 
the  water  will  contain  myriads  of  their  cast-off  skins.  The 
shell,  however,  is  not  shed. 


FIG.  141. — EARLY  STAGES  OF  A  BARNACLE:  A,  shortly  after  leaving  the  Egg;  e,  Eyes;  B, 
having  acquired  a  Bivalve  Shell,  and  just  before  becoming  attached,  represented  upside 
down ;  C,  Appearance  after  becoming  attached— Side-View ;  />,  Top- View  of  still  later  Stage, 
with  the  Shell  forming  around  it ;  E,  Side-View  of  Later  Stage,  showing  Appendages  pro- 
truded. (The  little  marks  at  the  sides  of  the  figures  indicate  the  natural  size  of  the  object. 
A,  B,  highly  magnified;  all  of  these  Views  are  magnified,  and,  with  the  exception  of  Z>, 
are  reduced  from  figures  of  C.  Spence  Bate.) 


WORMS.  153 

138.  The  young  come  from  eggs  as  free-swimming  ani- 
mals, furnished  with  eyes  and  jointed  appendages  provided 
with  hairs.  In  this  condition  they  swim  about  for  a  while, 
and  then  acquire  a  bivalve  shell,  and  in  this  state  remotely 
resemble  the  little  creatures  shown  in  Fig.  138. 

In  Fig.  141, .the  letter^,  represents  its  first  appearance 
from  the  egg.  Its  next  appearance  with  the  bivalve  shell  is 
shown  at  B.  After  remaining  a  free-swimming  animal  for  a 
while  it  becomes  attached  to  the  rock,  adhering  by  means  of 
appendages  on  the  head,  and,  then  moulting,  it  loses  its  former 
appearance ;  the  appendages  change  their  proportions,  new 
parts  are  added,  the  eyes  disappear,  a  limy  shell  gradually 
forms  around  it,  and  it  assumes  characters  entirely  unlike 
those  of  its  earlier  stages. 


CHAPTEK   XX. 

WORMS. 

139.  AMONG  the  animals  thus  far  studied,  having  a  body 
composed  of  segments,  the  pupils  have  seen  that  in  all  cases 
the  appendages  were  jointed,  that  is,  the  legs  and  antennae 
were  composed  of  distinct  segments  or  joints ;  and,  with  the 
exception  of  the  myriapods,  or  centipedes,  the  animals  pos- 
sessed a  limited  number  of  segments  to  the  body. 

In  the  group  of  animals  now  to  be  studied — the  worms — 
the  body  has,  generally  speaking,  an  indefinite  number  of 
segments,  and  there  are  no  jointed  appendages  attached  to  it. 


154  FIRST  BOOK  OF  ZOOLOGY. 

The  most  accessible  worm  is  the  common  earthworm. 
Specimens  can  be  collected  by  digging  for  them  in  damp 
earth ;  and  they  may  be  found  under  almost  any  board  or 
rock  which  has  lain  for  some  time. 

The  worms  may  be  washed  by  placing  them  in  a  bowl 
of  water,  where  their  movements  will  soon  remove  the 
dirt. 

The  body  is  composed  of  a  series  of  rings  or  segments, 
which  are  alike  in  form,  except  those  at  the  extremities, 
which  differ.  The  body  tapers  at  both  ends.  The  forward 
or  anterior  end  tapers  to  a  blunt  point,  while  the  hinder 
end  becomes  broad  and  flattened. 

By  carefully  watching  the  worm  when  it  shortens  up 
after  a  long  stretch,  there  will  be  seen,  projecting  from  the 
sides  and  lower  portion  of  each  ring,  minute  points,  which  are 
the  ends  of  little  bristles  protruding  from  openings  in  the 
sides.  These  bristles  as  they  move  project  backward. 


FIG.  142.— COMMON  EABTHWOKM. 


The  worm  moves  along  the  ground  by  the  aid  of  these 
bristles,  or  seta,  as  they  are  called.  The  body  alternately 
lengthens  and  shortens.  When  the  body  lengthens,  the  setse 


WORMS. 


155 


on  the  hinder  segments  of  the  body  prevent  its  stretching 
backward,  because  the  setae  pointing  backward  stick  into  the 
ground ;  the  body  therefore  can  lengthen  in  only  one  direc- 
tion, and  that  is  in  a  forward  one.  Then,  when  the  body 
shortens,  the  setse  in  the  forward  segments  stick  into  the 
ground,  and  the  hinder  part  of  the  body  is  drawn  up,  and 
by  this  method  the  creature  moves  along. 


FIG.  143. — EGG-CAPSULES  or  LEECH,  A;  AND  YOUJJO  LEECH,  B. — The  egg-capsules  are 
drawn  natural  size.  The  young  leech,  which  was  taken  from  the  egg-capsule,  is  drawn 
greatly  enlarged,  the  little  line  above  showing  its  natural  size. 

140.  Another  very  common  worm  is  the  leech.  Speci- 
mens may  be  collected  in  almost  any  pond  or  lake,  and  kept 
alive  in  jars  of  water.  The  creature  is  flat  and  broad,  and 
in  some  species  is  furnished,  at  the  hinder  end  of  the  body, 
with  a  sucker,  while  in  others  it  has  a  sucker  at  each  end  of 
the  body.  It  crawls  by  means  of  these  suckers,  and  swims 
through  the  water  by  an  undulating  movement  of  the  body. 
The  eggs  of  the  leech  are  laid  on  the  leaves  and  stems 
of  plants  which  grow  in  the  water.  The  eggs  are  contained 
in  little  oval  and  flattened  capsules,  and  these  capsules  are 
laid  side  by  side.  In  Figure  143  A  represents  two  capsules, 
in  which  the  little  leeches  can  be  seen  ;  B  represents  the 

figure  of  a  young  leech  greatly  enlarged,  showing  the  eyes 
8 


156  FIRST   BOOK  OF  ZOOLOGY. 

and  mouth,  at  one  end,  and  the  sucker  at  the  hinder  end. 
The  body  being  nearly  transparent,  the  internal  organs  show 
through. 

The  species  of  worms  in  fresh  water  are  few  in  number 
and  quite  small.  The  ocean  seems  to  be  their  true  home, 
all  along  the  sea-coast  occur  a  great  variety  of  worms,  many 
of  them  of  large  size. 

141.  Pupils  who  have  access  to  the  sea-coast  may  collect 
them  between  high  and  low  water  mark.     Certain  species 
may  be  obtained  by  turning  over  stones  and  others  by  dig- 
ging either  in  muddy  or  sandy  places.    After  a  violent  storm 
from  the  ocean,  many  kinds  of  worms  are  thrown  up,  and 
may  be  found  in  pools  left  by  the  receding  tide.     The  roots 
of  large  sea-weeds  also  afford  shelter  to  certain  kinds.     All 
of    these   creatures   may  be   kept   alive   for  a   few   days, 
though  considerable  care  is  required,  and  those  not  experi- 
enced in  keeping  salt-water  aquaria  are  warned  to  exclude 
these  animals. 

They  may  be  best  studied  by  being  placed  in  shallow 
bowls  or  plates,  and  there  will  be  much  to  admire  in  their 
graceful  motions  and  curious  ways. 

142.  A  very  common  form  is  found  under  stones  at  low 
tide.     The  body  is  composed  of  a  great  many  segments, 
from  the  sides  of  which  project  little  appendages  of  various 
shapes,  and  also  bunches  of  bristles  which  can  be  plainly 
seen  as  the  creature  moves.     The  head,  instead  of  being 
simple  -as  in   the   earthworm,  is  surmounted   by  various 
feelers. 


WORMS.  157 

Another  species  very  common  on  the  sea-shore,  under 
stones,  is  much  shorter  than  the  one  just  described.  It  has 
two  rows  of  oval  scales  along  the  back,  and  the  mouth  is  fur- 


FIG.  144.— A  COMMON  SEA- WORM. 


nished  with  powerful  jaws,  which  work  up  and  down.     When 
they  are  placed  in  alcohol  these  jaws  generally  protrude. 

143.  Some   species  have  a  curious  way  of  protruding 
their  oesophagus  when  they  seize  their  food,  at  the  end  of 


FIG.  145.— A  SEA- WORM  WITH  SCALES.— The  eyes  may  be  seen,  four  in  number,  between  the 

forward  scales. 

which  appear  the  jaws,  like  sharp  claw-shaped  teeth.  The 
following  figure  shows  the  anterior  end  of  one  of  these 
worms,  with  the  oesophagus  protruded,  in  the  act  of  se- 
curing its  prey. 

Certain  other  sea-worms  build  tubes  -  of  mud  or  sand 
in  which  they  live,  and  many  of   these  have  bunches  of 


158 


FIRST  BOOK  OF  ZOOLOGY. 


thread-like  feelers  on  the  head.     If  these  worms  are  taken 
from  their  tubes  and  placed  in  a  plate  of  sea-water  in  which 


FIG.  146.— ANTERIOR  PORTION  OF  A  SEA- WORM,  WITH  THE  (ESOPHAGUS  PROTRUDED.— o^ 
(Esophagus ;  .;',  Jaws ;  7t,  Head, 

are  contained  also  particles  of  dirt  or  sand,  they  will  begin 
to  build  a  new  tube,  and  for  this  purpose  the  threads  on  the 
head  will  stretch  out  like  delicate  rubber  cords,  and,  becoming 
entangled  in  the  particles  of  dirt,  will  draw  them  toward  the 
head,  when  the  appendages  on  the  body  will  mould  it  around 
them  in  the  shape  of  a  tube. 


i       A 

FIG.  147.— SEA- WORMS  WHICH  MAKE  LIMY  TUBES.— A,  Worm  with  Irregular  Tube,  the  line 
I  indicates  natural  length ;  £,  Worm  with  Spiral  Tube,  enlarged ;  (7,  Piece  of  Sea- Weed, 
showing  the  Appearance  and  Natural  Size  of  these  Spiral  Tubes  attached  to  it. 

Other  worms  deposit  a  hard,  shelly  tube  of  lime.     Some 
of  these  are  irregular  in  shape,  as  in  Fig.  147,  A.     Other 


WORMS.  159 

species  build  the  tube  in  a  coil,  looking  very  much  like  a 
snail-shell,  as  in  Fig.  147,  B.  This  form  is  very  common  on  the 
ordinary  rock-weed,  and  may  be  collected  in  the  debris  thrown 
up  by  the  waves.  Pupils  should  collect  these,  and,  if  possi- 
ble, watch  the  little  creatures  as  they  protrude  the  feathery 
appendages  which  surround  the  head.  In  the  forms  figured, 
one  of  the  appendages  is  modified  into  a  sort  of  plug,  and, 
when  the  worm  retires  within  the  tube,  the  plug  stops  up  the 
aperture  securely,  as  certain  snails  close  the  aperture  of  their 
shells  with  an  operculum. 

144.  In  studying  the  affinities  existing  between  animals 
in  order  to  group  them  together  naturally,  the  pupils  should 
learn  how  unsafe  it  is  to  judge  by  the  external  appearances  of 
the  animals  to  be  classified.  For  example,  the  little  worm  B 
just  described  has  a  coiled,  limy  shell,  which  might  easily  be 
mistaken  for  the  shell  of  a  snail.  Yet  the  slightest  examination 
of  the  soft  parts  within  shows  that  the  animal  is  made  up  of 
segments,  and  that,  minute  as  it  is,  there  are  bunches  of 
bristles,  or  setae,  projecting  from  the  sides  of  the  segments, 
and  from  these  and  other  characteristics  the  creature  is  proved 
to  be  a  true  worm,  having  no  affinities  with  the  snails.  The 
barnacles  too  have  a  limy  shell;  yet,  when  the  creatures 
within  are  examined,  their  affinities  with  the  crustaceans  are 
seen  at  once ;  and,  although  distinguished  naturalists  in  past 
times  grouped  them  with  the  shell-fish,  or  moll  asks,  they 
properly  belong  to  that  class  which  includes  the  lobster  and 
crab. 


160  FIRST  BOOK  OF  ZOOLOGY. 

CHAPTER  XXI. 

CONCERNING  NATURAL  GROUPS. 

145.  THE  pupils  have  seen,  thus  far,  not  only  that  the 
various  creatures  studied  differ  greatly  in  their  structure,  but 
that  some  are  complex  or  elaborate  in  their  characters,  while 
others  are  quite  simple.  But,  while  these  animals  differ 
so  much  among  themselves,  there  are  certain  characteristics 
which  many  of  them  have  in  common,  as  in  the  crustaceans 
and  insects,  for  example,  where  all  of  them  have  the  body 
divided  into  transverse  segments,  and  the  appendages  are  all 
jointed.  These  features,  which  are  common  in  large  assem- 
blages of  animals,  are  the  essential  characters  by  which  they 
are  brought  together  into  great  groups  or  divisions.  Thus, 
all  those  animals  which  have  the  body  jointed,  that  is  to  say, 
divided  into  a  series  of  segments,  as  in  the  worms,  crustaceans, 
and  insects,  form  the  great  branch  of  Articulates  of  Cuvier, 
because  Cuvier,  the  celebrated  French  naturalist,  first  applied 
the  name  Articulata  to  an  assemblage  of  animals  which  in- 
cluded the  worms,  crustaceans,  and  insects.  Since  then  natu- 
ralists have  separated  the  worms  from  the  crustaceans  and 
insects,  and  have  made  a  great  branch  of  them  called  Vermes. 

The  worms  differ  from  the  other  two  classes  with  which 
they  were  associated  by  Cuvier  in  not  having  jointed  legs, 
and,  generally  speaking,  in  not  having  the  segments  grouped 
together  into  regions. 


CONCERNING  NATURAL  GROUPS.  161 

In  worms,  too,  the  segments  are  far  more  numerous,  and 
there  is  no  fixed  or  definite  number  of  them  as  in  the  crus- 
taceans and  insects.  The  name  Articulates  is  therefore  aban- 
doned, and  the  crustaceans  and  insects  are  united  in  one 
branch  or  sub-kingdom,  and  called  Arthropods,  a  word  de- 
rived from  two  Greek  words,  meaning  jointed  foot,  while 
the  worms  are  embraced  under  another  sub-kingdom,  Vermes. 
The  clams,  oysters,  mussels,  snails,  and  the  squids  or  cuttle- 
fishes (a  class  of  animals  which  have  not  been  mentioned 
in  this  book),  have  certain  essential  features  in  common, 
and  so  they  are  included  in  another  great  branch  or  sub- 
kingdom  called  Mollusks,  from  a  Latin  word,  mollis,  mean- 
ing soft,  because  the  bodies  of  these  animals  are  soft,  though 
often  protected  by  a  hard  shell.  The  name  Mollusca  as 
applied  to  these  creatures  is  very  inexact,  because  there 
are  other  animals,  such  as  the  worms,  for  example,  which 
are  soft-bodied,  yet  having  no  relation  whatever  to  the 
shell-fish  or  Mollusca. 

146.  Now,  these  divisions  or  branches  not  only  include 
animals  which  are  simple  in  their  structure,  but  animals 
which  are  very  elaborate.  All  the  animals  in  each  great 
division,  however,  must  embrace  creatures  that  possess  the 
same  essential  characters.  "With  a  knowledge  of  these  essen- 
tial features,  it  has  been  customary  to  make  a  diagram  of  a 
theoretical  animal  out  of  these  characters  only.  This  theo- 
retical figure  is  called  an  archetype,  meaning  an  ancient  type, 
or  first  type,  and  the  characters  composing  it  are  hence  called 
type-characters*  or  typical  characters,  and  that  animal  which 


162  FIRST  BOOK  OF  ZOOLOGY. 

possesses  most  of  these  characters,  in  the  plainest  manner,  is 
called  a  typical  animal.  This  mode  of  presentation  applies 
as  well  to  smaller  groups  as  to  larger  ones.  Thus  in  the 
crustaceans,  the  lobster  and  crawfish  might  be  called  typical 
crustaceans,  as  being  the  types  or  representatives  of  the  class, 
while  a  barnacle  would  certainly  not  be  looked  upon  as  a 
typical  animal  of  this  class,  though  belonging  to  it.  In 
the  same  way  an  insect  without  wings  would  not  be  looked 
upon  as  a  type  of  the  insects,  because  one  of  the  leading 
characters  of  the  class  of  insects  is  the  possession  of  wings. 

In  making  systematic  tables  to  show  the  relative  grade 
an  animal  occupies,  the  simplest  groups  may  be  placed 
lowest  in  the  list  to  indicate  their  inferior  position.  For 
instance,  if  the  arthropods  were  to  be  arranged  in  a  sys- 
tematic table,  those  which  have  no  lungs,  but  gills  instead, 
would  be  placed  lowest,  because  it  has  been  found  in  other 
classes  of  animals  that  oftentimes  the  young  or  immature 
animal  has  gills  which  are  afterward  replaced  by  cavities  for 
the  purpose  of  breathing  air  direct,  and  the  immature  animal 
is  regarded  as  less  perfect,  or  lower  in  its  organization  than 
the  mature  or  adult  form.  Consequently  the  crustaceans 
would  be  placed  lowest  in  the  scale.  Then  would  come  the 
air-breathing  arthropods,  and  lowest  among  these  would 
come  the  spiders,  as  the  head  is  not  specialized  from  the 
thorax.  Next  would  come  the  myriapods,  as  in  these  the 
head  is  specialized  as  in  the  insects.  And,  finally,  the  true 
insects  would  come  highest,  as  here  the  legs  are  reduced  to 
three  pairs,  the  head  as  well  as  the  thorax  is  definitely  sepa- 


CHARACTERS  OF  VERTEBRATES.  163 

rated,  and  now  the  creature  has  added  to  it  wings  by  means 
of  which  it  has  new  means  of  locomotion.  This,  however, 
refers  only  to  the  most  prominent  types. 

If  the  table  is  to  be  arranged  to  show  the  highest  animals 
in  the  highest  part  of  the  column,  it  would  be  arranged  as 
follows  : 

{Insects. 
Myriapoda. 
Spider8' 


__  ___  ..- 

\  WATEK-BBEATHING  ABTHBOPODS.  -{  Crustaceans. 

This  is  classification  :  to  classify  animals  is  to  bring  those 
creatures  together  which  have  certain  leading  features  in 
common.  And  these  classes  may  be  divided  again  and  again 
into  smaller  groups. 

As,  for  example,  the  insects  proper  :  if  the  pupils  were  to 
divide  them  into  smaller  groups,  the  beetles  would  come 
together  as  one  group,  no  matter  what  their  shape  or  size  ; 
moths  would  form  another  group  ;  the  bugs  another  group, 
and  so  on. 


CHAPTER    XXII. 

CHARACTERS    OF   VERTEBRATES. 


147.  THE  lessons  thus  far  presented  have  been  upon  creat- 
ures belonging  to  three  great  divisions  of  the  animal  kingdom, 
the  Mollusks,  the  Arthropods,  and  the  Worms.  There  are 
many  other  groups  which  represent  other  great  divisions  of 
the  animal  kingdom,  of  which  no  mention  has  yet  been  made; 


164  FIRST  BOOK  OF  ZOOLOGY. 

and  upon  some  of  which  a  few  brief  lessons  will  be  given. 
The  material  to  be  collected  for  this  lesson  should  consist 
either  of  salamanders  (or  lizards,  as  they  are  incorrectly 
termed)  or  water-newts.  The  salamanders  may  be  found  in 
groves  and  forests,  under  rotten  logs  or  bark.  They  are 
absolutely  harmless,  though  many  people  regard  them  as 
poisonous.  Water-newts  are  similar  to  the  salamanders,  ex- 
cept that  they  live  in  the  water,  and  the  tail  is  often  provided 
with  a  fin. 

The  -following  figure  (Fig.  148)  represents  a  species  of 


FIG.  148. — COMMON  YELLOW  SPOTTED  SALAMANDER. 

salamander  common  to  the  Northern  States,  and  also  found 
at  the  South.  Its  color  is  bluish  black,  with  a  row  of  ir- 
regular shaped  yellow  spots  on  each  side  of  the  body. 

In  studying  the  external  characters  of  the  salamander, 
the  pupils  will  observe  the  following  features : 


CHARACTERS  OF  VERTEBRATES.          165 

The  animal  has  a  head  with  a  slight  constriction  between 
it  and  the  body.  The  head  has  two  eyes,  capable  of  being 
closed  by  movable  lids.  The  mouth  opens  transversely; 
that  is,  the  lower  jaw  is  on  the  under  part  of  the  head,  and 
moves  up  and  down.  In  the  insects  and  Crustacea,  the  jaws 
are  on  the  sides  of  the  head  and  open  sideways.  The 
jaws  have  minute  teeth,  and  in  large  salamanders  the  teeth 
can  be  felt  by  rubbing  the  finger  along  the  edge  of  the 
mouth.  On  the  front  of  the  head  there  are  two  holes  repre- 
senting the  nostrils.  The  creature  has  four  short  legs,  a  for- 
ward pair  and  a  hinder  pair ;  it  has  short  feet  also,  with  four 
toes  on  each  forward  foot,  and  five  toes  on  each  hinder  foot. 
The  tail,  which  is  quite  as  long  as  the  body  at  its  commence- 
ment, is  nearly  as  wide  as  the  body,  but  tapers  gradually, 
and  becomes  flattened  at  its  end. 

148.  How  different  in  every  respect  is  this  creature  from 
the  animals  thus  far  studied  in  this  book !  and  yet,  if  the  sal- 
amander is  compared  with  a  dog  or  cat,  the  characters  men- 
tioned above  will  be  found  in  each.  The  cat  has  also  a  head 
containing  two  eyes  with  movable  lids ;  the  lower  jaw  is  on 
the  under  part  of  the  head  and  moves  up  and  down  and  the 
mouth  opens  transversely ;  it  is  furnished  with  teeth,  there  are 
four  legs  with  feet  and  toes,  and  the  creature  has  a  tail.  But 
there  are  also  important  differences  between  the  two :  the  cat 
has  external  ears,  while  the  salamander  has  none,  though  it 
has  parts  which  enable  it  to  hear.  The  cat's  skin  is  covered 
with  hair  and  is  dry,  while  the  salamander  has  no  hair  upon 
it  and  the  skin  is  always  moist.  The  cat  has  sharp  claws, 


166  FIRST  BOOK   OF  ZOOLOGY. 

while  the  salamander  now  being  described  has  none.  On 
touching  the  cat  it  feels  warm,  while  the  salamander  feels 
cold  to  the  touch ;  with  the  cat  the  young  are  born  alive,  and 
the  little  kittens  have  the  same  general  features  as  the  parent- 
cat.  The  salamander  lays  a  number  of  eggs,  and  most  of  the 
species  lay  their  eggs  in  the  water ;  when  these  hatch,  the 
creatures  coming  from  them  have  no  lungs  and  cannot 
breathe  air  directly,  but  have  gills  instead.  More  curious 
still  is  the  fact  that,  when  the  young  creature  hatches  from 
the  egg,  it  has  no  legs,  these  appearing  afterward  as  the  ani- 
mal grows. 

The  following  figure  represents  the  appearance  of  a  young 
salamander  ten  days  after  hatching  from  the  egg.  The  gills, 
appearing  like  feathers,  are  seen  on  the  sides  of  the  neck. 


g 

FIG.  149— YOTTNG  SALAMANDER.— g,  </,  Gills.- (After  a  figure  by  Dr.  P.  E.  Hoy.) 


149.  Thus,  while  there  are  important  differences  between 
the  cat  and  the  salamander,  there  are  also  many  points  of  re- 
semblance ;  and,  if  the  arrangement  of  bones  constituting  the 
skeleton  be  examined,  a  still  closer  resemblance  may  be  seen. 
Within  the  body  the  salamander  has  a  series  of  bones  which 
together  form  the  skeleton.  The  most  important  part  of  the 
skeleton  consists  of  a  row  of  bones  which  runs  along  the  cen- 
tral line  of  the  back  of  the  body  from  the  head  to  the  tip  of 


CHARACTERS  OF  VERTEBRATES.          167 

the  tail.  This  row,  or  column  of  bones,  is  called  the  vertebral 
column,  and  the  bones  composing  it  are  called  the  vertebra. 
The  bones  of  the  head  combined  form  the  skull  or  cranium. 
The  ribs,  which  in  the  salamander  are  rudimentary,  are  at- 
tached to  tiie  sides  of  the  body  vertebrae.  The  bones  of  the 
fore  and  hind  legs  are  similar,  though  they  are  called  by 
different  names. 

A  series  of  bones  just  back  of  the  head,  the  longest  of 
which  is  the  shoulder-blade,  forms  the  scapular  arch  ;  to  this 
girdle  the  first  bone  of  the  fore-leg  is  joined.  Other  bones 
at  the  hinder  part  of  the  body  form  the  pelvic  girdle,  and  to 
this  the  first  bone  of  the  hind-leg  is  joined. 

150.  It  will  be  a  difficult  task  for  the  pupils  to  remove 
the  flesh  from  a  salamander  so  as  to  show  the  bones  united, 
and  it  will  also  be  difficult  to  prepare  the  skeleton  of  a  cat ; 
but  the  pupils  may  learn  something  about  the  bones  and  their 
attachments  by  gently  handling  the  creature.  Strauss-Durk- 
heim,  a  celebrated  naturalist,  when  he  was  writing  his  famous 
work  on  the  cat,  used  to  hold  one  of  these  animals  for  hours 
in  his  lap,  while  he  felt  of  the  muscles  and  other  portions  of 
the  body. 

The  following  figure  of  a  cat  shows  the  position  of  the 
bones  in  outline. 

Along  the  back  is  a  series  of  prominences  which  indicates 
the  vertebral  column,  or,  as  it  is  usually  called,  the  backbone 
or  spine.  On  the  sides  of  the  body  the  ribs  may  be  felt  like 
bars  or  ridges.  The  shoulder-blades,  or  scapula},  are  promi- 
nent bones,  forming  the  shoulders,  and  from  these  the  bones 
of  the  fore-legs  start. 


168 


FIRST  BOOK  OF  ZOOLOGY. 


The  bones  of  the  pelvic  arch,  or  pelvis,  may  be  readily 
detected,  and  from  these  the  hind-legs  start. 


89      G  5 


FIG.  150.— CAT,  WITH  BONKS  OF  EIGHT  SIDE  DRAWN.— Cra,  Cranium ;  so,  Scapula  or  Shoulder- 
Blade;  1,  Humerus;  2,  Radius  and  Ulna ;  3,  Carpus;  4,  Phalanges;  5,  Femur;  6,  Tibia 
and  Fibula ;  7,  Tarsus ;  8,  Metatarsus  ;  9,  Phalanges  ;  »,  Innominate  Bone — a  number 
of  Bones  combined,  forming  the  Pelvic  Arch;  «,  Vertebral  Column. 


151.  This  mode  of  examining  the  bones  is  suggested, 
since  it  would  hardly  be  possible  for  pupils  to  prepare  a 
proper  skeleton,  and  because  few  of  the  museums  of  the 
country  to  which  they  would  have  access  possess  skeletons 
of  this  kind.  Now  and  then  there  may  be  found  upon  the 
beach  a  nicely-cleaned  skeleton  of  a  dog  or  cat,  made  so  by 
little  creatures  which  have  fed  upon  the  flesh,  and  this  may 
be  used  for  study. 

As  unlike  as  the  salamander  and  cat  are  in  some  respects, 
in  many  characters,  both  external  and  internal,  they  are  re- 
markably alike. 

If  one  of  the  body  vertebrae  be  examined,  there  will  be 
found  a  central  bony  mass,  in  the  upper  side  of  which  will 
be  found  a  hole  which  is  made  by  the  bone  growing  up  from 


CHARACTERS  QF  VERTEBRATES.  169 

each  side  of  the  bony  mass,  arching  over,  and  uniting  above. 
All  of  the  vertebrae,  except  those  in  the  tail,  possess  this  chan- 
nel or  tube. 

Within  the  skull  is  a  mass  called  the  brain,  and  running 
from  this  through  a  hole  in  the  skull  is  a  long  white  cord 
called  the  spinal  cord  or  cerebro-spinal  cord,  and  this  always 
runs  along  on  the  back  of  the  spine  or  vertebral  column, 
passing  through  the  arch  or  hole  of  each  vertebra  just  de- 
scribed. In  fact,  the  spinal  cord  is  protected  from  injury  by 
passing  through  this  bony  tube. 

These  features  with  various  modifications  will  be  found 
in  all  animals  having  a  vertebral  column,  that  is,  a  central 
longitudinal  axis  either  of  bone  or  of  cartilage  above  which 
runs  the  spinal  cord. 

The  impulses  of  the  animal  to  move  originate  in  the 
brain  and,  passing  along  the  spinal  cord,  run  off  by  means  of 
nerves,  to  animate  the  movements  of  the  muscles.  As  a  proof 
of  this,  if  the-  spinal  cord  be  injured,  the  parts  behind  and 
below  it  are  rendered  helpless. 

The  ribs  passing  from  the  vertebrae  arch  below,  and 
form  another  and  much  larger  cavity,  in  which  are  contained 
the  organs  which  contribute  to  the  body's  growth,  such  as 
the  lungs  for  breathing,  the  heart  for  propelling  the  blood, 
the  stomach  for  digesting  the  food,  and  so  on.  The  follow- 
ing figure  represents  a  body  vertebra  to  which  are  attached 
a  pair  of  ribs  with  the  cavity  above,  in  which  is  contained 
the  spinal  cord  or  cerebro-spinal  cord,  and  the  cavity  below, 
in  which  are  contained  the  lungs,  heart,  stomach,  etc. 


170 


FIRST  BOOK   OF   ZOOLOGY. 


Cavity  below,  contain- 
ing lungs,  heart, 
stomach^  etc. 


FIG.  151. — A  YEKTEBRA  AND  A  PAIR  OF  BIBS,  FROM  A  CAT — CS,  Cavity  for  Cerebro-spinal 

Cord. 


152.  If  we  compare  the  hind-leg  of  the  salamander  with 
our  own  leg,  we  shall  find  essentially  the  same  arrangement 
of  parts,  namely:  the  leg  bending  at  a  joint  in  its  middle,  or 
the  knee-joint,  and  below  this  joint  another  one  called  the 
ankle-joint.  In  that  portion  of  the  leg  above  the  knee-joint 
there  is  one  long  bone  called  the  femur  which  joins  or  articu- 
lates with  the  pelvic  arch.  In  the  leg  below  the  knee-joint 
there  are  two  long  bones  side  by  side,  called  the  tibia  and 
fibula.  In  the  ankle-joint  there  are  a  number  of  small 
bones  closely  packed  together;  these  are  called  the  tarsal 
tones,  and  together  form  the  tarsus.  In  the  body  of  the 
foot  there  are  several  bones  upon  which  the  toes  rest,  and 


CHARACTERS  OF  VERTEBRATES.  171 

these  are  called  the  metatarsal  bones,  and  together  form 
the  metatarsus  ;  and  finally  come  the  bones  of  the  toes  called 
phalanges — a  long  series  of  names  to  remember,  yet  they 
apply  to  every  animal  possessing  a  vertebral  column  and 
having  legs. 

153.  The  fore-legs  of  the  salamander  have  similar  joints, 
the  elbow-joint  corresponding  with  the  knee-joint,  the  wrist- 
joint  corresponding  with  the  ankle-joint.  Above  the  elbow 
there  is  one  long  bone  called  the  humerus,  and  this  articu- 
lates with  the  shoulder-blade,  or  scapula,  as  it  is  called.  Be- 
low the  elbow  are  two  long  bones  side  by  side,  called  the 
radius  and  ulna.  In  the  wrist  are  a  number  of  small  bones 
called  carpal  bones,  which  together  form  the  carpus  /  and 
then  follow  longer  bones  corresponding  with  the  metatarsal 
bones,  and  these  are  called  the  metacarpal  bones,  and  to- 
gether form  the  metacarpus;  and  finally  the  bones  of  the 
fingers,  which  are  also  called  phalanges.  The  following  fig- 
ures represent  the  bones  of  the  right  fore  and  hind  leg  of 
a  species  of  salamander  common  to  the  Northeastern  and 
Middle  States. 

With  the  aid  of  a  good  hand-lens  the  pupils  may  see 
these  bones  in  the  leg  of  any  small  salamander  by  observing 
the  following  directions :  having  secured  a  live  salamander 
the  animal  may  be  killed  with  ether ;  now,  if  the  leg  be  cut 
off  and  gently  pressed  between  two  thin  pieces  of  glass,  the 
fiesh  will  be  found  sufficiently  translucent  to  show  all  the 
principal  bones  quite  distinctly : 


172 


FIRST  BOOK  OF  ZOOLOGY. 


femur. 


fibula. 
Ulna. 


Jiumerus 


radius 
ulna 


tarsus.  carpus 

metatarsus,  metacarpus 
phalanges.      phalanges 


HIND-LEG. 


FORE-LEG. 


FIG.  152.— HIND  AND  FOBE  LEG  OF  A  COMMON  WOOD  SALAMANDER.    (Those  figures  arc 

greatly  enlarged.) 


154.  All  animals  possessing  a  vertebral  column  have  es- 
sentially the  same  external  features  as  have  been  given  in 
the  preceding  lessons  on  the  salamander  and  the  cat ;  that 
is,  they  have  a  head  containing  two  eyes  with  movable  lids, 
a  mouth  opening  transversely  and  generally  furnished  with 
teeth ;  and,  with  the  exception  of  the  snakes  and  a  few  other 
creatures,  possessing  two  pairs  of  legs — a  fore-pair  and  a 


CHARACTERS   OF  VERTEBRATES.  173 

hind-pair — and  internally  having  a  skeleton  embracing  the 
features  already  noticed. 

In  the  fishes  the  head  is  continuous  with  the  body,  the 
fore  and  hind  legs  are  represented  by  fins,  one  pair  directly 
back  of  the  head,  corresponding  with  the  front-legs,  and  an- 
other pair  of  fins,  which  represent  the  hind-legs,  variously 
situated  behind,  below,  or  even  in  front  of  the  first  pair. 

155.  The  animals  which  possess  a  vertebral  column,  and 
hence  called  Vertebrates  (from  the  Latin  word  verto,  "I 
turn"),  are  the  fishes,  frogs,  toads,  salamanders,  snakes,  liz- 
ards, turtles,  crocodiles,  birds,  and  the  warm-blooded,  four- 
legged  beasts,  such  as  the  cat,  dog,  sheep,  horse,  and  elephant. 
These  last-mentioned  creatures  belong  to  a  large  class  of 
animals  called  Mammalia,  the  leading  features  of  which  are, 
that  the  young  are  born  alive,  and  the  mother  nurses  the 
young. 

The  fishes,  frogs,  toads,  salamanders,  snakes,  lizards,  tur- 
tles, and  crocodiles,  and  others  like  them,  are  cold-blooded, 
while  the  birds  and  mammals  are  warm-blooded,  and  all  of 
them,  except  the  mammals,  lay  eggs  from  which  their  young 
hatch.  The  fishes,  snakes,  lizards,  and  other  reptiles  are, 
generally  speaking,  covered  with  scales.  The  frogs,  toads, 
and  salamanders,  are  smooth-skinned ;  the  birds  are  covered 
with  feathers,  while  the  mammals,  with  few  exceptions,  are 
clothed  with  fur.  In  the  general  grouping  of  the  verte- 
brates the  fishes  and  amphibians — namely,  the  toads,  frogs, 
and  salamanders — form  one  group,  the  reptiles  and  birds 
form  another  group,  and  the  mammals  a  third  group. 


174  FIRST   BOOK   OF  ZOOLOGY. 

With  the  exception  of  fche  fishes,  the  similarity  in  the 
character  and  arrangement  of  the  bones  of  the  skeleton  of 
every  vertebrate  is  remarkable.  Even  the  birds,  which  are 
apparently  so  different  from  the  mammalia  on  the  one  hand 
and  the  turtle  and  salamander  on  the  other,  are  yet  quite 
similar  to  each  in  the  general  character  and  arrangement 
of  their  bones;  and  if  the  young  bird,  while  yet  in  the  egg, 
is  examined,  the  presence  and  affinities  of  certain  bones  are 
very  clearly  seen. 


CHAPTER  XXIII. 

BONES    OF   THE   LEG   AND   WING   OF.  BIRDS. 

156.  OUK  pupils  have  learned  by  this  time  how  impor- 
tant it  is  to  study  the  very  young  animal  in  order  to  deter- 
mine its  relationships.  Thus  in  studying  the  young  barna- 
cle the  affinities  of  the  creature  were  more  readily  recog- 
nized, and  in  the  affinities  of  the  parts  of  the  animal,  by 
studying  the  young  spider  the  palpi  were  more  easily  seen  to 
be  modified  legs.  Now,  as  an  interesting  example  of  the 
necessity  of  studying  the  young  or  early  condition  of  an 
animal,  a  bird  is  cited. 

The  fore-leg  in  the  bird  is  represented  by  its  wing,  and 
in  studying  the  bones  of  the  wing  of  an  adult  bird  but  little 
resemblance  can  be  seen  between  them  and  similar  parts  in 
other  vertebrates.  The  humerus,  radius,  and  ulna  are  plain 
enough,  it  is  true,  and,  when  the  pupil  has  a  chance  to  pick 


BONES  OF  THE  LEG  AND  WING  OF  BIRDS. 


175 


the  flesh  from  a  chicken's  or  a  turkey's  wing,  he  may  observe 
these  bones  easily  enough.  The  bones  of  the  wrist  and 
hand?  however,  seem  to  be  few  in  number  and  curiously 
grown  together. 


carpus 


metacarpus 


FIG.  153.— EIGHT  WING  OF  AN  ADULT  BIBD  BEEN  FROM  THE  INSIDB.— H,  Humerus ;  R,  Ra- 
dius; C;Ulna. 

157.  If,  however,  a  young  bird  is  taken  from  the  egg 
before  the  parts  are  fully  formed,  the  bones  of  the  wing 
will  be  found  separate  and  distinct,  and  the  relation  be- 
tween the  wing  of  the  bird  and  the  fore-leg  of  other  verte- 
brates becomes  more  fully  apparent. 

So  constant  are  the  characters  of  these  parts  in  all  birds, 
that  a  robin,  a  sparrow,  a  pigeon,  or  a  chicken,  will  reveal 
the  parts  quite  as  distinctly  as  the  larger  birds. 

In  the  embryo  bird,  that  is,  a  bird  while  still  in  the  egg, 
the  wing  and  leg  appear  far  more  alike  than  in  the  adult,  as 
may  be  seen  by  looking  at  the  following  figures  of  embryo 
birds  : 


176 


FIRST  BOOK  OF  ZOOLOGY. 


o 


A  B  C 

FIG.  154.— EMBRYO  BIRDS  IN  VARIOUS  STAGES  OF  DEVELOPMENT.— .4,  Chipping  Sparrow; 
£,  Petrel;  £7,  Tern  seen  from  above. 


If,  now,  the  bones  of  the  wing  of  an  embryo  bird  be  ex- 
amined, the  bones  of  the  extremity  of  the  wing,  instead  of 


humerus 


metacarpus 


phalanges 


FIG.  155.— EIGHT  WING  OF  AN  EMBRYO  BIRD  GREATLY  ENLARGED.  — Only   a  portion  of 
the  humerus  is  seen. 


BONES  OF  THE  LEG  AND   WING   OF  BIKDS. 


177 


beiog  closely  welded  together  as  in  Fig.  153,  are  found  to 
be  separate,  and  the  carpal  bones,  of  which  only  two  were 
apparent  in  the  full-grown  wing,  are  now  separate  and  four 
in  number.  The  wing  at  this  stage  looks  more  like  a  three- 
toed  foot.  Fig.  155  shows  the  appearance  of  the  wing  of  an 
embryo  bird. 

As  the  bird  develops,  the  bones  of  the  fingers  gradually 
approach  and  some  of  the  bones  grow  together  till  they 
present  the  appearance  shown  in  Fig.  153. 

158.  The  bones  of  the  leg  grow  together  in  the  same  way. 


tarsus J 


metatarsus 


phalanges* 


FIG.  156.— BONES  OF  THE  EIGHT  LEG  OP  AN  ADULT  BIKD.  — Only  the   lower  portion  ol 
the  tibia  and  fibula  is  drawn. 


178 


FIRST  BOOK  OF  ZOOLOGY. 


The  foregoing  figure  (see  page  177)  represents  the  lower 
portion  of  the  leg-bones  of  a  bird. 

It  will  be  seen  that  three  of  the  metatarsal  bones,  corre- 
sponding to  the  three  long  toes,  are  combined ;  their  ends, 
where  the  toes  join  on,  appearing  separate,  while  the  meta- 
tarsal bone  of  the  short  toe  on  the  side  remains  separate  from 
the  others. 

At  the  ankle-joint,  or  tarsus,  there  are  no  separate  tarsal 
bones  to  be  seen,  nor  would  their  existence  be  known,  except 
theoretically,  without  an  examination  of  the  embryo. 

The  following  figure  represents  the  appearance  of  the  leg 


fibula. 

tibia. 


tarsus. 


metatarsus. 


phalanges. 


FIG.  157. — RIGHT  LEG  OF  AN  EMBRYO  BIRD  GREATLY  ENLARGED. — Only  She  lower  portion 
of  the  tibia  and  fibula  is  drawn. 


BONES  OF  THE  LEG  AND  WING  OF  BIRDS.  179 

of  an  embryo  bird  greatly  enlarged,  showing  the  bones  in 
place. 

At  this  early  stage,  not  only  the  metatarsal  bones  are 
seen  separate,  but  the  bones  of  the  tarsus,  four  in  number, 
are  well  marked  and  distinct.1 

The  many  strange  modifications  in  the  shape  and  propor- 
tions of  the  legs  of  vertebrate  animals  are  accompanied  by 
similar  changes  in  the  arrangements,  number,  and  proportion 
of  the  bones  of  these  parts. 

Thus,  in  the  short  leg  of  the  salamander  (see  Fig.  152) 
the  bones  of  the  tarsus  occupy  a  space  about  as  long  as  that 
of  the  metatarsus.  In  birds,  on  the  contrary,  the  tarsus  is 
very  short,  while  the  metatarsus  is  very  long. 

159.  If  the  pupils  will  observe  the  hind-leg  of  the  toad 
or  frog,  they  will  see  that  not  only  is  it  much  longer  than  the 
fore-leg,  but  that  an  extra  joint  seems  to  be  added  in  the  foot. 
An  examination  of  the  bones  shows  that  the  first  two  tarsal 
bones  are  very  long,  while  the  other  tarsal  bones  are  very 
short ;  so  that  in  this  case  the  tarsus  combined  is  much  longer 
than  the  metatarsus.  The  following  figure  represents  the 
right  hind-leg  of  a  young  toad  while  still  in  the  tadpole 
state,  though  the  adult  shows  the  same  features. 

The  above  brief  lessons  on  the  vertebrates  do  not  even 
embrace  an  outline  of  the  structure  and  habits  of  any  of 
the  classes,  and  they  are  given  only  as  suggestions  toward  a 
method  of  study,  and  to  point  out  the  essential  paths  to  fol- 

1  The  author  has  seen  the  tarsal  bone,  marked  *,  in  the  heron,  tern,  and  sea- 
pigeon. 

9 


180 


FIRST  BOOK  OF  ZOOLOGY. 


low,  in  order  to  gain  an  insight  into  the  affinities  existing 
between  the  various  groups  composing  this  great  branch  of 
animals. 


Jj 

bula. 

J1 

- 

_ 

tiUa. 

Jo  

tarsus. 

CO-.... 

[metatarsus. 


pTialanges. 


FIG.  158.— BONES  OF  THE  EIGHT  LEG  OF  A  YOTTNG  TOAD  GREATLY  ENLARGED.— The  femur 
is  not  shown  in  this  drawing ;  the  tibia  and  fibula  are  combined  together. 


There  are  still  other  large  classes  of  animals  forming 
branches  or  sub-kingdoms  quite  distinct  from  those  already 
studied,  and  represented  by  animals  which  live  in  the  sea, 
such  as  the  star-fish,  sea-urchin,  jelly-fish,  and  sea-anemone, 
of  which  no  mention  will  be  made  in  this  book.  There  are 
also  many  classes,  belonging  to  branches  already  touched 
upon,  which  have  not  been  alluded  to.  These  will  be  fully 
dealt  with  in  the  second  book,  now  in  preparation. 


CLASSES  AND  SUB-KINGDOMS. 


181 


CHAPTER    XXIY. 

CLASSES    AND     SUB-KINGDOMS. 

THE  following  figures  illustrate  the  classes  and  sub-king- 
doms which  have  been  dealt  with  in  this  book,  with  their 
technical  names : 

SUB-KINGDOM  MOLLUSCA  (Clams,  Snails,  /Squids,  etc.). 

Class  Gasteropoda  (snails,  periwinkles,  limpets,  etc.). — 
Animals  whose  bodies  are  generally  inclosed  in  a  mantle  or 
sac,  which  usually  secretes  a  shell  composed  of  one  piece,  and 
this  often  assuming  a  spiral  shape.  The  body  rests  upon  a 
broad,  creeping  disk  called  the  foot,  and  this  part  represents 
the  ventral  portion  or  belly  of  the  animal.  The  name  Gas- 
teropoda is  derived  from  two  Greek  words,  gaster,  the  belly, 
and  pous,  foot.  The  following  figures  represent  a  few  ani- 
mals of  this  class : 


182 


FIRST  BOOK   OF  ZOOLOGY. 


GASTEBOPODS. 

Class  Acephala  (clams,  oysters,  mussels,  etc.). — Animals 
whose  bodies  are  protected  by  a  mantle  which  secretes  a  bi- 
valve shell,  or  a  shell  composed  of  two  pieces.  They  have 
no  well-defined  head,  and  hence  the  name  Acephala,  de- 
rived from  two  Greek  words,  a,  without,  and  cephale,  head. 
These  animals  are  also  called  Lamellibranchiates,  because 
the  gills  form  leaf-like  membranes  or  plates  on  the  sides  of 
the  body  ;  the  word  being  derived  from  a  Latin  and  a  Greek 
word,  lamella,  a  plate,  and  firanchia,  gill.  The  following 
figures  represent  a  few  animals  of  this  class  : 


CLASSES  AND  SUB-KINGDOMS. 


183 


ACEPHALA. 


SUB-KINGDOM  AETHEOPODA  (Insects,  Spiders,  Centipedes, 
Crabs,  etc.). 

Class  Insecta  (beetles,  bugs,  butterflies,  etc.). — Animals 
whose  bodies  are  made  up  of  segments  grouped  together  in 
three  regions,  the  head,  thorax,  and  abdomen  ;  having  three 
pairs  of  jointed  legs,  and  one  or  two  pairs  of  wings,  and 
breathing  air  through  openings  in  the  sides  of  the  body. 
The  word  insecta  comes  from  a  Latin  word,  inseco,  I  cut  into, 
referring  to  the  distinct  separation  of  the  body  into  regions. 


184 


FIRST  BOOK  OF  ZOOLOGY. 


INSECTS. 


Class  Myriapoda  (centipedes,  millepedes).  Animals  com- 
posed of  many  segments.  These  not  apparently  combined 
into  regions,  except  the  head,  which  is  distinct.  The  number 
of  pairs  of  legs  coinciding  with  the  number  of  segments. 
Breathing  air  through  openings  in  the  sides  of  the  body. 

The  word  myriapoda  is  derived  from  two  Greek  words, 
murioi,  ten  thousand,  smdpous,  foot. 


A  MYBIOPOD. 


CLASSES  AND  SUB-KINGDOMS.  185 

Class  Arachnida  (spiders).  Animals  whose  bodies  are 
segmented.  The  segments  grouped  together  into  two  re- 
gions, the  cephalo-thorax  and  the  abdomen.  Having  four 
pairs  of  legs,  and  breathing  air  through  openings  in  the  body. 

The  word  arachnida  is  derived  from  a  Greek  word, 
arachne,  spider. 


ARACHNIDS- 


Class  Crustacea  (lobsters,  crabs,  barnacles,  etc.).  Difficult 
to  define,  but  including  animals  which  pass  through  a  series 
of  moults  in  their  growth,  though  in  this  respect  resembling 


186 


FIR§T   BOOK   OF  ZOOLOGY. 


CETJSTACEANS. 


the  spiders,  and  breathing  by  means  of  gills,  and  in  this  re- 
spect differing  from  other  arthropods. 

SUB-KINGDOM  YEKMES  (worms).     Class  Annelida  (angle- 


CLASSES  AND   SUB-KINGDOMS.  187 

worms,  leeches,  certain  sea-worms,  etc.).  Animals  whose 
bodies  are  made  up  of  an  indefinite  number  of  segments, 
bearing  appendages  which  are  not  jointed,  and  in  the  larger 
number  of  groups  having  bunches  of  bristles  or  setce  upon 
the  sides  of  the  body  which  act  as  supplementary  organs  of 
locomotion.  The  name  annelida  is  derived  from  the  Latin 
word  annulus,  a  ring. 


WOBMS. 


SUB-KINGDOM  YERTEBRATA,  with  the  following  classes, 
which  have  been  only  briefly  alluded  to  :  Fishes,  Amphibians, 
Reptiles,  Birds,  Mammals.  According  to  a  late  classifica- 
tion of  Professor  Huxley's,  these  classes  would  stand  Ichthy- 
opsida,  which  includes  the  Fishes  and  Amphibians;  San- 


188 


FIRST   BOOK  OF  ZOOLOGY. 


ropsida,  which  includes  the  Reptiles,  and  Birds ;  and  lastly 
Mammalia. 

Ichthyopsida  is  derived  from  two  Greek  words,  ichthus, 
a  fish,  and  opsis,  appearance.  Sauropsida  comes  from  two 
Greek  words,  sauros,  a  lizard,  and  apsis,  appearance. 


O 


TEETEBBATES. 


NOTICE  TO  TEAOHEES. 


To  those  who  care  to  pursue  the  subject  more  in  detail  with 
their  classes,  or  to  present  the  history  of  those  groups  of  ani- 
mals of  which  no  mention  has  been  made  in  this  book,  the 
author  would  suggest  the  following  publications,  among  many 
others  of  value,  as  works  of  reference  : 

Woodward's  Manual  of  Mollusca. 

Marine  Mammalia  and  American  Whale-Fishery.     By  Captain  C.  M.  Scammon, 

U.  S.  R.  M. 

Sea-side  Studies  in  Natural  History.     By  Mrs.  Agassiz  and  Alexander  Agassiz. 
Corals  and  Coral  Islands.     By  Prof.  J.  D.  Dana. 
Packard's  Guide  to  the  Study  of  Insects. 
Insects  injurious  to  Vegetation.     Harris. 
The  Annual  Reports  of  the  State  of  Missouri  on  the  Noxious,  Beneficial,  and 

other  Insects.     By  Prof.  C.  V.  Riley. 
United  States  Fish  Commissioners'  Report  for  187l-'Y2.     By  Prof.  Spencer  F. 

Baird.     Containing  valuable  illustrated  chapters  on  the  Mollusca,  Crustacea, 

Worms,  etc.,  by  Prof.  A.  E.  Verrill  and  S.  I.  Smith. 
Key  to  North  American  Birds.     By  Dr.  Elliot  Coues,  U.  S.  A. 
Osteology  of  Mammalia.     Flower. 

A  History  of  North  American  Birds.     By  Baird,  Brewer,  and  Ridgeway. 
Canadian  Entomologist. 
Forms  of  Animal  Life.     Rolleston.- 
Methods  of  Study  in  Natural  History.     By  Prof.  L.  Agassiz. 


190  NOTICE  TO  TEACHERS. 

And  for  general  information,  the  works  of  Darwin,  Huxley, 
Owen,  Wallace,  Mivart,  Lubbock,  and  the  Duke  of  Argyle, 
and  also 

Nature,  a  weekly  magazine  published  in  London,  and  containing  an  infinite 
variety  of  contributions  from  English  and  Continental  naturalists. 

The  American  Naturalist,  a  popular  illustrated  magazine  of  natural  history. 
Edited  by  Dr.  A.  S.  Packard  and  F.  W.  Putnam,  and  published  in  Salem,  Massa- 
chusetts ;  containing  a  vast  amount  of  information  by  Lockwood,  Allen,  Coues, 
Verrill,  Smith,  Stearns,  Scudder,  Emerton,  Gill,  Putnam,  Packard,  Hyatt,  Mann, 
Marsh,  Dall,  Cooper,  Gill,  Cope,  Ridgeway,  Wood,  Abbott,  Trippe,  Le  Conte, 
Wyman,  Dawson,  Grote,  Mayer,  Gentry,  Shaler,  Wilder,  Aikin,  Treat,  Perkins, 
Riley,  Agassiz,  Dana,  Hill,  Uhler,  Edwards,  Tuttle,  Tenney,  Ward,  Hagen,  Hartt, 
Shimmer,  Hartshorne,  Ritchie,  Tilsdale,  Hoy,  Orton,  Lewis,  Leidy,  Brigham, 
Scammon,  Binney,  Stimpson,  Collins,  Fowler,  Walker,  Jordan,  Wright,  Norton, 
Maynard,  Canfield,  Fellowes,  Endicott,  and  others. 

The  Popular  Science  Monthly,  edited  by  Prof.  E.  L.  Youmans,  and  published 
by  D.  Appleton  &  Co.,  New  York ;  containing  valuable  illustrated  articles  by 
American  and  European  naturalists. 

Every  school  library  should,  if  possible,  contain  a  complete  set  of  Nature,  the 
Naturalist,  and  The  Popular  Science  Monthly.  For  special  descriptions  of  species, 
the  miscellaneous  collection  of  the  Smithsonian  Institution,  with  contributions 
by  Stimpson,  Gill,  Bland,  Binney,  Prime,  Tryon,  and  others.  Also  the  American 
Journal  of  Science  and  Art,  and  the  publications  of  the  Boston  Society  of  Natu- 
ral History,  Philadelphia  Academy  of  Sciences,  New  York  Lyceum  of  Natural 
History,  Buffalo  Academy  of  Natural  Sciences,  California  Academy  of  Natural 
Sciences,  Portland  Society  of  Natural  History,  Museum  of  Comparative  Zoology, 
Peabody  Academy  of  Science,  etc. 

All  these  last-named  publications  should  be  found  in  the 
larger  libraries  of  the  country. 


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Annum.  Computed  on  the  Basis  respectively  of  360  and  865  Days  to  the  Year, 
and  arranged  for  the  Averaging  of  Accounts  by  H.  B.  BRYANT,  H.  D.  STRATTON, 
and  S.  S.  PACKARD.  Official  Tables  of  the  United  States  Treasury  Depart- 
ment. 1  vol.,  large  4to.  Half  roan,  $5.00. 

Bryant  &  Stratton's  Commercial  Law  for  Business  Men. 

Revised  by  AMOS  DEAN.    1  large  vol.,  8vo.    Cloth,  $8.25 ;  law  sheep,  $4.00. 

Veitelle's  Mercantile  Dictionary. 

A  Complete  Vocabulary  of  Technicalities  of  Commercial  Correspondence.  Cloth, 
$1.50. 

Jevons's  Money  and  the  Mechanism  of  Exchange. 

By  "W.  STANLEY  JEVONS,  M.  A.,  F.  E.  S.,  Professor  of  Logic  and  Political  Econ- 
omy in  the  Owens  College,  Manchester.  1  vol.,  12mo.  Cloth,  $1.75. 

Clarke's  Weights,  Measures,  and  Money,  of  all  Nations. 

Compiled  by  F.  W.  CLARKE,  8.  B.,  Professor  of  Physics  and  Chemistry  in  the 
University  of  Cincinnati.  1  vol.,  12mo.  Half  bound,  $1.50. 

Price's  Currency  and  Banking. 

By  BONAMY  PRICE,  Professor  of  Political  Economy  in  the  University  of  Oxford. 
1  vol.,  12mo.  Cloth,  $1.50. 

Haswell's  Book-Keeping  ly  Double  Entry, 

Explained  and  practically  illustrated  in  a  Complete  Eecord  of  Mercantile  and 
Financial  Transactions,  including  Rules  and  numerous  Examples  in  Commercial 
Calculations.  Designed  for  Schools,  the  Counting-House,  and  Private  Instruc- 
tion. By  CHARLES  H.  HASWELL,  Civil,  Marine,  and  Mechanical  Engineer ;  Mem- 
ber of  the  American  Society  of  Civil  Engineers,  etc.  8vo.  Half  morocco,  $3.00. 
Blanks  for  the  same,  $1.70. 


D.  APPLETON  &  CO.,  PUBLISHERS,  549  &  551  BROADWAY,  NEW  YORK. 


PEIMEES 

IN    SCIENCE,   HISTORY  AND   LITERATURE, 
IS  mo*    Flexible  cloth,  45  cents  each. 


I.— Edited  by  Professors  HUXLEY,  ROSCOE,  and  BALFOUR  STEWART. 

SCIENCE  PRIMERS. 


Chemistry H.  E.  ROSCOE. 

Physics BALFOUR  STEWART. 

Physical  Geography,  A.  GEIKIE. 

Geology A,  GEIKIE. 

Physiology M.  FOSTER. 

Astronomy J.  N.  LOCKYER. 


Botany J.  D.  HOOKEB. 

Logic W.  S.  JEVONS. 

Inventional    Geometry,  W.  G. 
SPENCEB. 

Pianoforte FRANKLIN  TAYLOR. 

Political  Economy,  W.  S.  JEVONS. 


II. — Edited  by  J.  R.  GREEN,  M.  A.,  Examiner  in  the  School  of  Modern 
History  at  Oxford. 

HISTORY  PRIMERS. 


Greece C.  A.  FYFFE. 

Rome M.  CBEIGHTON. 

Europe E.  A.  FREEMAN. 


Old.  Greek  Life...J.  P.  MAHAFFY. 
Roman  Antiquities,  A.S.WILKINS. 
Geography GEOBGE  GKOVE. 


in.— Edited  by  J.  R.  GREEN,  M.  A. 
LITERATURE  PRIMERS. 


English  Grammar.... R.  MORRIS. 
English  Literature STOPPORD 

BROOKE. 

Philology J.  PEILE. 

Classical  Geography M.  F. 

TOZEB 


Shakespeare E.  DOWDEN. 

Studies  in  Bryant J.  ALDEN. 

Greek  Literature R.  C.  JEBB. 

English  Grammar  Exercises. 

R.  MORRIS. 
Homer W.E.GLADSTONE. 


(Others  in  preparation.) 

The  object  of  these  primers  is  to  convey  information  in  such  a  manner  as  to 
make  it  both  intelligible  and  interesting  to  very  young  pupils,  and  so  to  dis- 
cipline their  minds  as  to  incline  them  to  more  systematic  after-studies.  They 
are  not  only  an  aid  to  the  pupil,  but  to  the  teacher,  lightening  the  task  of  each 
by  an  agreeable,  easy,  and  natural  method  of  instruction.  In  the  Science  Series 
some  simple  experiments  have  been  devised,  leading  up  to  the  chief  troths  ot 
each  science.  By  this  means  the  pupil's  interest  is  excited,  and  the  memory  is 
impressed  so  as  to  retain  without  difficulty  the  facts  brought  under  observation. 
The  woodcuts  which  illustrate  these  primers  serve  the  same  purpose,  embellish- 
ing and  explaining  the  text  at  the  same  time. 

D.  APPLETON  &>  CO.,  549  &  551  Broadway,  New  York. 


'  SCHOOL  READERS, 

CONSISTING  OF  FIVE  BOOKS. 


W.  T.  HAEEIS,  LL.D,,  A.  J.  RICKOFF,  A.  M.,  MAEK  BAILEY,  A.  M., 

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St.  Louis,  Mo.  Cleveland,  O.  Yah  College. 


BETAIL  PRICES. 

APPLETONS' FIRST  READER $o  25 

APPLETONS' SECOND   READER 40 

APPLETONS' THIRD  READER 56 

APPLETONS' FOURTH   READER 70 

APPLETONS'  FIFTH  READER..  1  25 


CHIEF     MERITS. 

These  Readers,  while  avoiding  extremes  and  one-sided  tendencies,  combine 
into  one  harmonious  whole  the  several  results  desirable  to  be  attained  in  a 
series  of  school  reading-books.  These  include  good  pictorial  illustrations,  a  combi- 
nation of  the  word  and  phonic  methods,  careful  grading,  drill  on  the  peculiar  com- 
binations of  letters  that  represent  vowel-sounds,  correct  spelling,  exercises  well 
arranged  for  the  pupil's  preparation  by  himself  (so  that  he  shall  learn  the  great 
lessons  of  self-help,  self-dependence,  the  habit  of  application),  exercises  that 
develop  a  practical  command  of  correct  forms  of  expression,  good  literary  taste, 
close  critical  power  of  thought,  and  ability  to  interpret  the  entire  meaning  of  the 
language  of  others. 

THE    AUTHORS. 

The  high  rank  which  the  authors  Lave  attained  in  the  educational  field  and 
their  long  and  successful  experience  in  practical  school-work  especially  fit  them 
for  the  preparation  of  text-books  that  will  embody  all  the  best  elements  of  mod- 
ern educative  ideas.  In  the  schools  of  St.  Louis  and  Cleveland,  over  which  two 
of  them  have  long  presided,  the  subject  of  reading  has  received  more  than  usual 
attention,  and  with  results  that  have  established  for  them  a  wide  reputation  for 
superior  elocutionary  discipline  and  accomplishments.  Feeling  the  need  of  a 
series  of  reading-books  harmonizing  in  all  respects  with  the  modes  of  instruc- 
tion growing  out  of  their  long  tentative  work,  they  have  carefully  prepared  these 
volumes  in  the  belief  that  the  special  features  enumerated  will  commend  them 
to  practical  teachers  everywhere. 

Of  Professor  Bailey,  Instructor  of  Elocution  in  Tale  College,  it  is  needless  to 
speak,  for  he  is  known  throughout  the  Union  as  being  without  a  peer  in  his  pro- 
fession. Eis  methods  make  natural,  not  mechanical  readers. 

D.  APPLETON  &>  CO.,  549  &  551  Broadway,  New  York. 


THE  WORLD  OF  WATERS. 


The  Commercial  Products  of  the  Sea  ; 

Or,  Marine  Contributions  to  Food,  Industry,  and  Art.  By  P.  L. 
SIMMONDS.  With  Thirty-two  Illustrations.  1  vol,  12mo,  cloth.  484 
pages.  Price,  $1.75. 

"It  ia  certain  that  a  large  part  of  our  race  would  have  to  perish  but  for  the 
countless  forms  of  life  which  swarm  in  the  depths  of  the  sea.  Mr.  Simmonds 
has  brought  together  the  statistics  as  to  the  extent  of  the  various  large  fisheries 
of  the  world,  whether  they  supply  food  or  objects  of  industrial  value.  Of  the 
most  exquisite  and  highly- valued  product  of  the  sea,  the  pearl,  and  of  the  methods 
of  obtaining  it,  and  managing  the  pearl-oyster  beds,  Mr.  Simmonds  gives  a  care- 
ful account.  To  the  sponge,  coral,  amber,  turtle,  and  other  fisheries,  he  devotes 
the  same  detailed  attention."— JV.  Y.  Sun. 

"Filled  with  important  and  interesting  facts  concerning  marine  contributions 
to  food,  industry,  and  art.1'— Boston  Journal. 

"A  vast  amount  of  information  is  here  collected,  and  the  general  reader,  as 
well  as  the  specialist,  will  find  the  work  full  of  interest."— Buffalo  Daily  Courier. 


11  The  Multitudinous  Seas," 

With  Illustrations.  By  S.  G.  W.  BENJAMIN.  Forming  Number  23 
of  Appletons'  "  New  Handy- Volume  Series."  18mo.  Paper,  price, 
25  cents. 

"  Another  view  of  the  inexhaustible  fascinations  of  the  deep  is  displayed  in 
'  The  Multitudinous  Seas,'  by  S.  G.  W.  Benjamin.  Free  from  statistics,  and 
written  in  a  fluent  and  picturesque  style,  by  one  who  has  traveled  far  and  near 
over  the  face  of  the  waters,  it  deals  little  with  subjects  of  industrial  importance, 
but  enables  one  to  gain,  in  an  easy  and  attractive  way,  a  new  insight  into  the 
myriad  strange  aspects  of  the  ocean.  St.  Elmo's  lights,  water-spouts,  submarine 
volcanoes,  icebergs,  cyclones,  the  beautiful  and  curious  creatures  found  floating 
on  the  surface  of  the  sea,  are  only  a  part  of  the  themes  on  which  it  discourses." 
-X.  T.  Sun. 


Flguier's  Ocean   World : 

A  Descriptive  History  of  the  Sea  and  its  Inhabitants.  With  425 
beautiful  Illustrations.  Carefully  revised.  By  E.  PERCIVAL  WRIGHT, 
M.  D.  1  vol.,  12mo.  Cloth,  $3.00 ;  half  calf,  $5.00 ;  full  calf,  $6.00. 


D.  APPLETON  &  CO.,  PUBLISHERS,  549  &  551  BROADWAY,  N.  Y. 


THE 


EXPERIMENTAL  SCIENCE  SERIES. 


In  neat  12mo  volumes,  bound  in  cloth,  fully  illus- 
trated..    Price  per  volume,  $1.OO. 


THIS  series  of  scientific  books  for  boys,  girls,  and  students  of  every  age,  was  de- 
signed by  Prof.  Alfred  M.  Mayer,  Ph.  D.,  of  the  Stevens  Institute  of  Technology, 
Hoboken,  New  Jersey.  Every  book  is  addressed  directly  to  the  young  student,  and 
he  is  taught  to  construct  his  own  apparatus  out  of  the  cheapest  and  most  common 
materials  to  be  found.  Should  the  reader  make  all  the  apparatus  described  in  the  first 
book  of  this  series,  he  will  spend  only  $12.40. 


NOW  KEADY: 

I.— LIGHT. 

A  Series  of  Simple,  Entertaining,  and  Inexpensive  Experiments  in  the  Phenomena  of 
Light,  for  Students  of  every  Age. 

By  ALFRED  M.  MAYEE  and  CHAELES  BAENAED. 

II.— SOUND: 

A  Series  of  Simple,  Entertaining,  and  Inexpensive  Experiments  in  the  Phenomena  of 
Sound,  for  the  Use  of  Students  of  every  Age. 

By  ALFEED  MAESHALL  MAYEE, 

Professor  of  Physics  in  the  Stevens  Institute  of  Technology ;    Member  of  the  National 
Academy  of  Sciences;  of  the  American  Philosophical  Society,  Philadelphia;  of 
the  American  Academy  of  Arts  and  Sciences,  Boston ;  of  the  New  York 
Academy  of  Sciences ;  of  the  German  Astronomical  Society ;  of 
the  American  Otological  Society ;  and  Honorary  Mem- 
ber of  the  New  York  Ophthalmological  Society. 

IN  ACTIVE  PREPARATION; 

III.  Vision  and  the  Nature  of  Light. 

IV.  Electricity  and  Magnetism. 
V.  Heat. 

TI.  Mechanics. 
VII.  Chemistry. 

VIII.  The  Art  of  experimenting  with  Cheap  and  Simple  In- 
struments. 

D.  APPLET  ON  &  CO.,  Publishers,  549  &  551  Broadway,  New  York. 


THE  EXPERIMENTAL  SCIENCE  SERIES. 


LIGHT: 

A  Series  of  Simple,  Entertaining,  and  Inexpensive  Experiments  in  the 
Phenomena  of  Light,  for  the  Use  of  Students  of  Every  Age. 


BY  ALFRED  M.  MAYER  AND  CHARLES  BARNARD. 


NEAT  12MO  VOLUME,  FULLY  ILLUSTRATED.      .      .      CLOTH,  PRICE,  $1.00. 


"  Professor  Mayer  has  invented  a  series  of  experiments  in  Light  which  are 
described  by  Mr.  Barnard.  Nothing  is  more  necessary  for  sound-teaching  than 
experiments  made  by  the  pupil,  and  this  book,  by  considering  the  difficulty  of 
costly  apparatus,  has  rendered  an  important  service  to  teacher  and  student  alike. 
It  deals  with  the  sources  of  light,  reflection,  refraction,  and  decomposition  of 
light.  The  experiments  are  extremely  simple  and  well  suited  to  young  people." 
— Westminster  JRemew. 

"This  work  describes,  in  simple  language,  a  number  of  experiments  illus- 
trating the  principal  properties  of  light,  by  means  of  a  beam  of  sunlight  admitted 
into  a  dark  room,  and  various  contrivances.  The  experiments  are  highly  in- 
genious, and  the  young  student  can  not  fail  to  learn  a  great  deal  from  the  book. 
As  an  example  of  the  effective  experimental  method  employed,  we  may  specially 
mention  the  device  for  illustrating  the  refraction  of  light.  This  book  is  specially 
designed  '  to  give  to  every  teacher  and  scholar  the  knowledge  of  the  art  of  experi- 
menting.' "—The  Quarterly  Journal  of  Science  (London). 

"A  singularly  excellent  little  hand-book  for  the  use  of  teachers,  parents,  and 
children.  The  book  is  admirable  both  in  design  and  execution.  The  experi- 
ments for  which  it  provides  are  so  simple  that  an  intelligent  boy  or  girl  can 
easily  make  them,  and  so  beautiful  and  interesting  that  even  the  youngest  chil- 
dren must  enjoy  the  exhibition.  The  experiments  here  described  are  abundantly 
worth  all  that  they  cost  in  money  and  time  in  any  family  where  there  are  boys 
and  girls  to  be  entertained.1'— New  York  Evening  Post. 

"  The  experiments  are  capitally  selected,  and  equally  as  well  described.  The 
book  is  conspicuously  free  from  the  multiplicity  of  confusing  directions  with 
which  works  of  the  kind  too  often  abound.  There  is  an  abundance  of  excellent 
illustrations.1'— New  York  Scientific  American. 

"The  experiments  are  for  the  most  part  new,  and  have  the  merit  of  com- 
bining precision  in  the  methods  with  extreme  simplicity  and  elegance  of  design. 
The  value  of  the  book  is  further  enhanced  by  the  numerous  carefully-drawn  cuts, 
which  add  greatly  to  its  beauty."— American  Journal  of  Science  and  Arts. 


D.  APPLETON  &  CO.,  549  &  651  BROADWAY,  NEW  YORK. 


THE  EXPERIMENTAL  SCIENCE  SERIES. 


SOUND: 

A  Series  of  Simple,  Entertaining,  and  Inexpensive  Experiments  in  the 
Phenomena  of  Sound,  for  the  Use  of  Students  of  Every  Age. 

BY  ALFRED  MARSHALL  MAYER, 

Professor  of  Physics  in  the  Stevens  Institute  of  Technology;  Member  of  the 
National  Academy  of  Sciencee,  etc. 


Uniform  with  "  LIGHT"  first  volume  of  the  Series, 


NEAT  12no  VOLUME,  FULLY  ILLUSTRATED.      .       .      CLOTH,  PRICE,  $1.00. 


"  The  object  of  the  volume  is  to  present  the  leading  phenomena  of  Sound  in  a 
simple  and  entertaining  manner,  by  the  use  of  such  materials  as  are  almost  every- 
where at  hand,  and  with  apparatus  which  any  ingenious  student  can  construct 
for  himself.  To  present  the  elements  of  an  abstruse  subject  in  such  a  way  as  to 
make  the  exposition  easily  comprehensible  by  a  mind  not  specially  trained  in 
it,  and  at  the  same  time  correct  and  satisfactory  from  a  scientific  point  of  view, 
is  one  of  the  most  difficult  undertakings  in  the  work  of  an  instructor.  Add  to 
this  the  task  of  bringing  the  experimental  illustration  of  a  science  like  that  of 
acoustics,  which  requires  such  refinement  in  the  apparatus  and  its  manipulation, 
within  the  resources  of  every  one,  and  we  have  the  difficulty  very  greatly  in- 
creased. Professor  Mayer's  well-known  experimental  skill  has  enabled  him  to 
accomplish  the  work  in  an  admirable  manner,  and  he  has  laid  under  obligation 
to  him  not  only  the  student  and  the  amateur  experimenter,  but  the  teacher,  who 
will  derive  many  valuable  suggestions  as  to  his  own  work  from  this  little  volume. 
The  subject  is  arranged  in  a  very  clear  and  methodical  manner,  and  treated  in  a 
vivacious  and  entertaining  style.  The  experiments,  many  of  which  are  novel, 
unite  extreme  simplicity  with  elegance  of  conception  and  scientific  precision, 
and  can  not  fail  to  interest  and  stimulate  the  minds  of  the  students  into  whose 
hands  the  volume  may  fall.  The  illustrations,  which  are  numerous,  are  ex- 
cellently done,  and  give  the  book  a  very  attractive  appearance.11— American  Jour- 
nal of  Science  and  Arts. 

"  It  would  really  be  difficult  to  exaggerate  the  merit,  in  the  souse  of  consum- 
mate adaptation  to  its  modest  end,  of  this  little  treatise  on  4  Sound.'  It  teaches 
the  youthful  student  how  to  make  experiments  for  himself,  without  the  help  of 
a  trained  operator,  and  at  very  little  expense.  These  hand-books  of  Professor 
Mayer  should  be  in  the  hands  of  every  teacher  of  the  young."— New  York  Sun. 

"  An  admirably  clear  and  interesting  collection  of  experiments,  described  with 
just  the  right  amount  of  abstract  information  and  no  more,  and  placed  in  pro- 
gressive order.  The  recent  inventions  of  the  phonograph  and  microphone  lend 
an  extraordinary  interest  to  this  whole  field  of  experiment,  which  makes  Pro- 
fessor Mayer's  manual  especially  opportune." — Boston  Courier. 


D.  APPLETON  &  CO.,  549  &  551  BROADWAY,  NEW  YORK. 


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